Damn this took a while to go through. Detailed thoughts are included under each stage, but I also included my quick opinion on each one. First rating is Standard, second is with Hazards Off.
N = Neutral
CP = Counterpick
2P = Doubles only
TBD = Needs testing
BAN = Banned
Also, since we have limited information on the four brand new stages, it is literally just my best guess based on what I’ve seen so far.
Battlefield - N
Not much to say here. It’s the standard by which all other stages are judged.
By default this makes the “Battlefield version” of all stages (Alpha versions?) legal as well.
Big Battlefield - 2P
Probably too big for singles, but I think this is easily viable for doubles. Possibly a counter pick?
Final Destination - N
Similar to Battlefield, this one is obviously a standard choice, as are all Omega versions.
Peach’s Castle - TBD
The one from 64. Only notable hazards are the bumper at the top and the moving platform, but general stage layout is not ideal. Almost definitely banned.
NO HAZARD: May be an argument for counterpick, but depends on exactly how much changes.
Kongo Jungle - BAN/2P
I like this stage, but it’s pretty big, and the Barrel Cannon leads to some silly shenanigans. Banned.
NO HAZARD: Even without the Barrel, the stage is still too big for singles, but might be playable in doubles.
Hyrule Castle - BAN
The original “too big” stage. Wacky platform layout. Multiple walls and a cave of life. Tornado. Super banned.
NO HAZARD: Even minus the tornado, the rest of the stage is a problem. Banned.
Super Happy Tree - BAN/TBD
AKA Yoshi’s Island 64. No real hazards to speak of, aside from the fading clouds. But the stage is huge and makes for easy camping. Banned.
NO HAZARD: If this removes the clouds completely, I think there’s strong argument for doubles and counterpick.
Dream Land - N
The original Battlefield. Aside from Whispy Woods occasionally giving you a soft push, not much to judge here. Neutral.
NO HAZARD: With no Whispy, it’s just a larger Battlefield. So… technically still fine, but why bother?
Saffron City - BAN
Heh. This stage is silly and fun and very not good for competition. Banned
NO HAZARD: Even with Pokemon turned off, the cityscape layout doesn’t lend well to competitive. You could argue for doubles, but I wouldn’t.
Mushroom Kingdom - BAN
Walkoffs; Warp pipes; Way too big. Banned.
NO HAZARD: You lose the piranha plants and (probably) the lift in the middle, but it’s still a bad stage.
Princess Peach’s Castle - BAN
The Melee one. Banzai Bill is the (literal) biggest problem here, since it effectively sections off one side of the stage when it explodes. But the central tower kind of does that anyway. Banned.
NO HAZARD: Again, maybe you could do doubles here, but I doubt it would be a good idea.
Rainbow Cruise - BAN/TBD
I’ve never liked this stage. It’s an auto-scrolling stage and it’s way too easy to get lost. Banned.
NO HAZARD: If the ship just doesn’t move, this could maybe be a counterpick stage. Otherwise I’d still lean toward banned.
Kongo Falls - BAN
This stage has such a fun layout… except for that damn rock at the bottom. Also Klaptraps are a big nuisance. Banned.
NO HAZARD: With no Klaptraps, I really want to say counterpick on this, but I know it all comes down to the stupid rock.
Jungle Japes - BAN
Pfft. Haha. This stage was always dumb and somehow got dumber when swimming was introduced. Banned.
NO HAZARD: Even though the Klaptraps on this stage are incredibly annoying, they aren’t even close to the biggest problem with it.
Great Bay - BAN
This stage is a great sendup to Majora’s Mask but it is a BAD fighting stage. Super Banned.
NO HAZARD: Getting rid of Tingle and the Turtle can’t save this stage.
Temple - BAN
There are no hazards to speak of on this stage, but it’s just so damn big. Save it for 8-player Smash. Banned.
Brinstar - BAN/TBD
The acid would not be so bad if it only covered the bottom platform, but it doesn’t. Also, the destructible parts of the stage create some really weird interactions. Banned.
NO HAZARD: Removing the acid takes care of the biggest problem this stage has, but if it also makes the bubbles at the bottom non-breakable this stage is basically neutral.
Yoshi’s Island (Melee) - BAN
What a silly, bad stage. That stupid middle section creates so many SDs, and it’s only one bad part. Super banned.
NO HAZARD: Making the blocks unbreakable removes one issue but creates others. Still not a good stage.
Yoshi’s Story - N
It’s almost like Battlefield, but it’s also not. Fly Guys are barely worth mentioning, and most people seem to like the little safety cloud.
NO HAZARD: Removing the cloud would actually hurt the stage IMO, but regardless it’s still one of the best available.
Fountain of Dreams - N
The classic. Probably the most desired stage in the series. Battlefield with platform variety. 100% Neutral.
NO HAZARD: If this removes the moving platforms, then it’s just Battlefield but prettier.
Green Greens - BAN/CP?
Slightly better than Yoshi’s Island, but not by much. Bombs and apples and small blast zones make for bad stage. Banned.
NO HAZARD: If all the blocks are completely removed I think this could be a counterpick.
Cornelia - BAN
There are a lot of lasers on this stage and they all shoot at the worst possible time. Banned.
NO HAZARD: No lasers is better, the Great Fox is still really big and the covered section on the right is still a problem.
Venom - BAN
Peach’s Flying Castle, plus LASERS! Banned.
NO HAZARD: The lasers are actually the least problematic thing about the stage.
Pokémon Stadium - CP/N
I always questioned this stage in Melee, because even though it mostly has good layouts, the Fire and Rock transformations inevitably cause stalling. Still, it’s overall a good stage, though I wouldn’t grant it higher than counterpick.
NO HAZARD: With transformations off, PS1 offers a simple but unique platform layout. Instant Neutral.
Onett - BAN
Any stage that has no bottom blast zone is auto-disqualified. Banned.
NO HAZARD: Removing the cars changes nothing.
Mushroom Kingdom II - BAN
Walk-offs on both sides of the stage make it a no-go. Banned.
NO HAZARD: Birdo is not the problem with this stage.
Brinstar Depths - BAN/TBD
The gimmick of this stage is really cool and interesting, not to mention it looks gorgeous in HD. That said, the shape of the stage causes too many janky variations. Banned.
NO HAZARD: Depending on which configuration the stage starts in, this could maybe be a counterpick.
Big Blue - BAN
NO HAZARD: I’m actually really curious what this version of the stage plays like, but I doubt it would change anything.
Fourside - BAN
Same issues as Saffron City. Banned.
NO HAZARD: I assume this removes the UFO, which doesn’t really change anything.
Delfino Plaza - CP?/N
I’ve never had an issue with this stage, but every transition has its own little quirks, so I definitely understand why people don’t like it. Counterpick at best.
NO HAZARD: A unique platform that doesn’t make any stops. OK then.
Mushroomy Kingdom - BAN
This concept for this stage is neat, but in practice it’s just AWFUL. Constant walkoffs, few pits, and it auto-scrolls. Super banned.
NO HAZARD: I can’t even picture what this version of the stage would be.
Figure-8 Circuit - BAN
The karts on this stage are barely noticeable, but it has Onett syndrome. Banned.
NO HAZARD: Removes the least problematic problem of the stage.
WarioWare, Inc - BAN/N
Oof. This is another stage where I love the concept but it just destroys the competitive value. Banned.
NO HAZARD: YES. SO MUCH YES. I think this is the stage that most needed a hazardless option. Super unique platform setup makes this an easy neutral choice.
Bridge of Eldin - BAN
A huge stage with double walkoffs and occasionally places a janky pit in the middle. No thanks. Banned.
NO HAZARD: Let’s turn this into Final Destination with walkoffs. Still no thanks.
Norfair - BAN/CP
I’ve never thought the lava mechanic here is that bad, but I will acknowledge that it completely dictates the pace and position of the match. Banned.
NO HAZARD: I think the unique platform setup would make this a great counterpick option.
Frigate Orpheon - CP
Anyone who has ever complained about this stage is dumb. Yeah, I said it. I’ve always loved this stage and have always thought it’s competitively viable EVEN WITH THE FLIPPING MECHANIC. The fact that the right side of the stage has grabbable ledges now makes it even more viable.
NO HAZARD: No excuses on this one. It’s probably still a counterpick, but you could easily make an argument for neutral.
Yoshi’s Island - N
The Brawl one. Arguably better than Yoshi’s Story in terms of neutrality, aside from the randomness of ghosts.
NO HAZARD: Remove the ghosts and it’s pretty much one of the best neutral choices in the game.
Halberd - CP/N
Similar to Frigate, I’ve never thought the hazards on this stage were difficult to navigate. The one exception is that the laser creates a huge zone of death for a few seconds. I’d still argue for counterpick, though.
NO HAZARD: I am curious if this stays on the moving platform or on the deck of the ship itself. Either way, the removal of ship hazards makes it a good neutral choice.
Lylat Cruise - CP/N
A Star Fox level that has no hazards… and yet it still gets complaints because of tilting jank. I still say counterpick.
NO HAZARD: If the level doesn’t tilt, I personally say this level should be a neutral option.
Pokémon Stadium 2 - BAN/N
OK, while I have mild complaints about PS1 transformations, I definitely understand the issues with PS2. Every single transition creates disruptive terrain. Banned.
NO HAZARD: While this definitely makes the stage playable, we’re still left with the question of “why not just Pokemon Stadium 1?”
Port Town Aero Dive - BAN/TBD
NO HAZARD: Depending on where this is set, it could go anywhere from banned all the way up to neutral.
Castle Siege - BAN/CP
Sigh. If it wasn’t for the walkoffs in the middle section, I think this stage would be great as a counterpick. But… it has those walkoffs. Banned.
NO HAZARD: Apparently this just stays in the initial configuration. Definitely counterpick; possibly neutral.
Distant Planet - BAN
A sloped walkoff on one side, a giant instant-death hazard on the other, and random movement disruptions. That’s a big nope.
NO HAZARD: Even removing the bulborb and the rain, the stage is still pretty iffy. I’d say no.
Smashville - N
The neutral stage. No reason not to keep the trend going.
NO HAZARD: Apparently the platform remains stationary in the middle. Still good.
New Pork City - BAN
Temple but worse. Super banned.
NO HAZARD: Removing the Chimera doesn’t change how huge the stage is.
Summit - BAN
This is a fun stage with a group of friends. This is a bad stage for competition for a whole host of reasons. Banned.
NO HAZARD: If you stay at the top of the mountain, maybe this could be a counterpick? Otherwise it’s still a terrible choice.
Skyworld - BAN
This stage is so close to viable that it makes me sad. If the platforms were fall through instead of destructible it would be amazing. But it’s not. Banned.
NO HAZARD: Being unable to destroy platforms actually makes this stage worse in my opinion.
Shadow Moses Island - BAN
This stage only has one blast zone until you break the columns and then it has Onett syndrome. Banned.
NO HAZARD: This stage only has one blast zone. Super banned.
Luigi’s Mansion - 2P?
In my opinion, the biggest problem with the stage is how big it is. I think it’s fine aside from that.
NO HAZARD: Being unable to destroy the mansion should make this an interesting doubles stage.
Pirate Ship - BAN/TBD
Everything in the background is a terrible nuisance, but the two biggest offenders are the catapult and the KO zone under the ship. Banned.
NO HAZARD: If (and only if) the front of the ship doesn’t immediately kill you, I actually think this is a good counterpick.
Spear Pillar - BAN
Hm. A giant stage where Legendary Pokemon cause incredibly disruptive effects. Oh, and also a cave of life. No thank you. Banned.
NO HAZARD: It’s still big and it’s still easy to run away through the tunnel.
75m - BAN
NOOOOOOOOOOOOPE. Arguably the worst stage in the game.
NO HAZARD: There is nothing you could change to make this stage better.
Mario Bros - BAN
Onett but with caves of life. Banned.
NO HAZARD: I barely notice the enemies on this stage, so removing them changes nothing.
Hannenbow - BAN
NOOOOOOOOOOOOPE. The only stage that might be worse than 75m.
NO HAZARD: Removing the tadpoles takes away the only thing that makes the stage marginally interesting.
Green Hill Zone - BAN
Sometimes the ground breaks away randomly. The rest of the time it’s Onett with hills. Banned.
NO HAZARD: It still has double walkoffs.
3D Land - BAN
A more interesting Mushroomy Kingdom. With that said, it’s still a scrolling stage with too many walkoffs. Banned.
NO HAZARD: Depends on how much of the stage is still used, but probably not.
Golden Plains - BAN
Onett with a gimmick instead of hazards. Banned.
NO HAZARD: Double walkoffs.
Paper Mario - BAN
I love how this stage looks; I hate how this stage plays. The ship is the only mildly acceptable transformation, but it’s hardly worth it. Banned.
NO HAZARD: If it is only the ship, then maybe. Otherwise, no.
Gerudo Valley - BAN
This stage is gorgeous in HD, but it’s basically a slightly less tedious Bridge of Eldin. Banned.
NO HAZARD: Curse you double walkoffs!
Spirit Train - BAN
NOOOOOOOOOOOOOPE. Big Blue but worse.
NO HAZARD: Still no.
Dream Land GB - BAN
Every configuration has double walkoffs. Banned.
NO HAZARD: Every configuration has double walkoffs.
Unova Pokemon League - BAN/N
Honestly, the biggest issue with this stage are the staircases on the sides creating some janky interactions. The Pokemon in the background are telegraphed and not even that powerful. Counterpick at best, but probably banned.
NO HAZARD: Another unique platform setup. Neutral for sure.
Prism Tower - CP/N
My favorite stage from 3DS and probably the best transitional stage in the series. Aside from the walkoffs at the very beginning, there is literally nothing wrong with any part of the stage. I’d argue for neutral, but definitely counterpick at worst.
NO HAZARD: I’m not sure if anything actually changes or if it’s just the transition platform. Either way the rating stays the same.
Mute City SNES - BAN
It’s… better than the original Mute City? I think? It’s a really neat idea, but it doesn’t have a bottom blast zone, so that’s an auto-ban from me.
NO HAZARD: As with Big Blue, I’m curious what this looks like, but severely doubt it will change anything.
Magicant - BAN
Flying Man is the main offender here. He’s mobile, incredibly strong, and takes forever to kill. The small platform underneath is also a camping nightmare. Banned.
NO HAZARD: So close and yet so far. That bottom platform is a nuisance. Maybe you could say counterpick, but I wouldn’t.
Arena Ferox - 2P or CP
Some transformations are great. Some are troublesome. I’d probably still push for counterpick, but not that hard. Probably fine for doubles.
NO HAZARD: Depends on which form is used, but I’d assume it becomes a lot better.
Reset Bomb Forest - BAN/CP
First area is actually not that bad. The second part is GOD AWFUL. Banned.
NO HAZARD: I don’t think the central pit is an auto-ban. If anything, I think it creates more variety. I’d say this makes it an interesting counterpick.
Tortimer Island - 2P
None of the hazards here are more than a nuisance, even the shark. But the stage is really big. Counterpick at best for singles. Fine for doubles IMO.
NO HAZARD: Overall rating doesn’t change, but the stage is better this way.
Balloon Fight - BAN
What a weird stage. It technically has walkoffs… except you can’t actually walk off. Bumpers, lightning, and that damn fish just make it that much worse. Banned.
NO HAZARD: Better, but still not good.
Living Room - BAN
Onett with falling debris. Hard pass.
NO HAZARD: Onett with fallen debris. Pass.
Find Mii - BAN/CP?
The cage is a swinging wall and the Dark Emperor is a major problem. Banned.
NO HAZARD: This is a possible counterpick option, but not a very good one.
Tomodachi Life - 2P
Even though there’s technically no hazards here, the platform setup makes it very hard to catch fast characters. It’s probably OK for doubles, but I’d say no for singles.
NO HAZARD: Literally the same.
Pictochat 2 - BAN
Some of the transformations are just wacky, similar to WarioWare. Fun, but not fair. Banned.
NO HAZARD: Depending on which drawing is used, this could be playable, but I wouldn’t count on it.
Mushroom Kingdom U - BAN/CP
The first area is fine. All the other areas have some major jank in them. Banned.
NO HAZARD: If it stays in the first area, I’d say counterpick.
Mario Galaxy - BAN
Curved Onett. Next.
NO HAZARD: Nothing changes.
Mario Circuit - BAN/TBD
Awesomely fun stage. I would play this at every opportunity if given the chance. But it has some really silly interactions with the track. Banned.
NO HAZARD: Really depends on what the layout is.
Skyloft - CP/N
Delfino but better IMO. I think in all the different configurations there’s only one walkoff option. Personally I’d push for counterpick. If Delfino is legal, this one should be, too.
NO HAZARD: According to footage, the hazardless version stays on the moving platform the whole time with a unique platform setup. If this is true, it easily jumps to neutral.
Great Cave Offensive - BAN
NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOPE. Super banned.
NO HAZARD: It’s still big. And bad.
Kalos Pokemon League - BAN/N
OK, so I love this stage… except for the Steel chamber. Both variations are just terrible. Everything else is mostly fine, but that one section ruins the entire stage. Banned.
NO HAZARD: Another Pokemon stage with a simple, unique platform setup. Huzzah!
Coliseum - BAN
Onett with variable platforms.
NO HAZARD: Hazardless Bridge of Eldin.
Flat Zone X - BAN
Onett meets WarioWare. Super banned.
NO HAZARD: Double walkoffs
Palutena's Temple - BAN
NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOPE. New Pork but worse. Super banned.
NO HAZARD: Same, but even less interesting.
Gamer - BAN/TBD
Mother is one of the most entertaining background hazards in the game. However, even thought the stage doesn’t change, the initial configuration is random each time. Overall, not nearly as bad as some, but still ban-worthy.
NO HAZARD: If there is a standard platform configuration I definitely think this stage should be a counterpick.
Garden of Hope - BAN/2P
This is a large stage with so much going on, and all of it is disruptive. Banned.
NO HAZARD: Still big. Possibly fine for doubles, though.
Town and City - N
Smashville 2.0, though not as universally neutral as its predecessor.
NO HAZARD: Hopefully it doesn’t just become another Battlefield.
Wii Fit Studio - BAN
NO HAZARD: Same
Boxing Ring - BAN
NO HAZARD: The lights don’t drop, but otherwise the same.
Gaur Plains - BAN
Huge, with almost nothing to fill the space. Metalface is the only thing that makes the stage interesting at all, but he’s also a major nuisance.
NO HAZARD: You take away the only interesting thing… and it’s still a bad stage.
Duck Hunt - CP
The only thing possibly wrong with this stage is camping the top of the tree, which is barely a problem considering how small it is.
NO HAZARD: Removing the dog makes the stage more boring, but overall doesn’t change much about it.
Wrecking Crew - BAN/TBD
Blech. This is a bad stage from every angle. Banned
NO HAZARD: If there is a standard, simple configuration, then maybe this upgrades to counterpick, but I wouldn’t count on it.
Pilotwings - BAN
Venom mixed with Lylat Cruise. Shares the major issues of both which combine to make a worse overall stage.
NO HAZARD: Even if it only stays on one plane, the big problems remain.
Wuhu Island - BAN/N
Some areas are quite good. Others are downright awful. I would ban it, but if it wasn’t, Delfino Plaza and Prism Tower are much better variations of the same thing.
NO HAZARD: This has a unique platform configuration and doesn’t make any stops. Yes please.
Windy Hill Zone - BAN/2P
The springs and windmill are annoying but generally not really a problem. Mostly it’s just that the stage is too large.
NO HAZARD: I’d argue for doubles.
Wily Fortress - BAN/N
I love everything about this stage except Yellow Devil. Which unfortunately makes the stage competitively unplayable.
NO HAZARD: Not sure what the platform layout becomes, but easily a neutral option without the Devil.
PAC-LAND - BAN
Mushroomy Kingdom but somehow worse. Super banned.
NO HAZARD: Arguably less annoying, but no less terrible.
Super Mario Maker - BAN/TBD
Randomness is this stage’s strength, but is also what makes it uncompetitive. Banned.
NO HAZARD: If you completely remove the point of the stage and make a standard configuration, it might be a counterpick.
Suzaku Castle - BAN
A very weird platform layout combined with a walkoff edge. Honestly it feels more true to the Street Fighter series to only play this one in Omega form.
NO HAZARD: There aren’t any hazards to remove, so nothing changes.
Midgar - BAN/N
Damn this is a cool stage. All the Summons look amazing… and all of them are busted. Banned.
NO HAZARD: Sadly, this just becomes another Battlefield with limited music.
Umbra Clock Tower - CP/TBD
A few great transformations combined with a few not so great ones. I always thought if PS1 was legal, this one should be too, but I am obviously alone in this sentiment.
NO HAZARD: Depending on which transformations appear (or how many) this either stays as counterpick or moves up to neutral.
New Donk City - CP*
Delfino Plaza but better. No true hazards have been shown yet, and it will really depend on the overall platform configurations, but I have a strong leaning toward counterpick on this. Also, JUMP UP SUPERSTAR!
NO HAZARD: So far, I don’t think this changes anything meaningful.
Great Plateau Tower - BAN*
Man, it’s so SO close to being great. I’m curious how much damage it takes to break the roof, but so far it seems like a lot, which really hurts this stage’s chances.
NO HAZARD: Apparently, the tower can’t be destroyed at all, which basically makes the stage unplayable and that’s just too sad for words.
Moray Towers - 2P*
It’s Tomodachi Life with ramps. Not sure if that makes it better or worse. Definitely has better music, though.
NO HAZARD: As far as I’m aware, no hazards have been shown for this stage, so I don’t know if this changes anything.
Dracula's Castle - BAN/CP*
This one just exudes creepy-cool awesomeness. In fact, there’s so much awesome (in the form of monsters) that there’s no chance in hell it will be competitively viable.
NO HAZARD: The real question for me is how much of an issue the small wall on the right is. If it’s negligible or only abusable in specific circumstances, this could totally be a counterpick. If it becomes a big problem, it’s probably still banned.