Even discounting meter spending, bursts, and combo difficulty you generally have combos that have better meter gain, more damage, better setups, more corner carry, reset opportunities, and style. Granted, you’ll rarely have to pick between all of them and rather tend to have 2-3 options. Like right now I’m playing Raven in Xrd. I can do my combos such that I either get a chance to sneak in a command grab reset, a corner carry and more damaging option, an oki option, or build some Excitement gauge. Granted I find the oki option to be superior 90% of the time because he’s a vortex character but the other options are perfectly valid if I either think they won’t catch onto my reset, or perhaps am willing to spend 25% meter for the oki after the corner carry, or have been landing all my dunks and want the last tick of Excitement to get free combos after a command grab.
Now, Raven doesn’t really have any hard combos, but my other character, Axl, does! He’s got all sorts of shenanigans he can go for with TK Bomber. That lets a more execution heavy player get better oki or damage against some characters in certain situations. But he doesn’t need to do it; it’s a bonus for the character and he works perfectly well without it. This is good combo design. Everyone can play the character and scale what they get out to how confident they are in their own combo skill. Axl also has the choice of combo enders for his juggles midscreen, going for either damage + tech traps, full screen push and burst safety, or a hard knockdown for oki. They’re all damn useful in their own ways.
Eh, combos in SFIV tended to add execution depth but they didn’t really give you the same choices you get in Xrd with some characters. Like with Sakura the entirety of her combo choices generally came down to “am I confident I can hit these links” and “do I want to spend meter for the EX Tatsu juggle to charged fireball setup.” I guess you could also use MP Shouken over HP for the auto-5f safejump? That and the link/FADC system meant that the barrier to entry for doing combos was really high. It wasn’t very good.
Not to say that SFV has a great one. With Necalli you really get a choice of oki + V Gauge vs corner carry if you can confirm super quickly, otherwise it’s really “spend meter” vs “don’t spend meter” because there’s no reason to go other routes. It’s easier to pull off (which is good) but there’s not really any difference in depth.