It really depends on the “is it worth it for the effort” factor and how you treat items like these, I know a lot of people are purists around here and just want to collect, so it’s a completely different POV if you just want to preserve, compared to most of us in tech talk who want to not only preserve but also improve.
Let’s say a Konami Hyperstick for the PS1. it’s considered rare and a collectible by many. Modding it involves desoldering the button board, but its the only way to replace microswitches, the buttons too are unique Seimitsu with specialized colors specially made for Hyperstick, would you replace that? the stick doesn’t need to be modded IMHO due to the parts being already arcade quality, otherwise its just an aesthetic choice, or just repair/functionality mods (different PCB etc). Then again, replacing parts for it is easy and its a case of “might as well change this and that” and since it doesn’t involve permanent case alterations, you can put it back to stock if wanted (if you didn’t fuck up something somewhere)…
Namco stick’s aren’t worth modding. It’s a crappy stick, lets face it. You don’t want one for functionality, its meant to be collected and for you to say you have 4 of them. Modding it is a hassle. you could say, its EX2 level hassle. Why would you mod it? it devalues it as d3v mentioned, but also you’re better off using that energy buying a better stick.
Then there’s weird premium sticks like the HSS-0130. The Virtua stick pro. You can leave it stock, but due to its age and time it was from, it’s probably not in the best state functionality wise. It uses saturn encoders, has (by now) crappy worn out gunky sun-yellowed buttons, and the Levers show its age with poor handling and control. So would you leave it stock? sure if you just wanna resell.
But if you wanna use it you’d want to refurbish and modify it. (lets be REALLY sensible here, who would go back to playing on Saturn ports of fighters when MAME or superior ports exists, on better more convenient displays and modern consoles). It doesn’t help that the VSP uses sega control panels, so your options have drastically multiplied on how extensive you want to modify it.
Would you keep it stock and just rely on converters? or completely re-do the whole thing, with a modern multi-console PCB, a fresh new set of buttons and joysticks, on a better condition control panel. By the end of it, you’d have spent more than you’d want, but now that stick is fully functional, and its benefits start to become clear because you can hook it up to anything you want to, not just Saturn, it has better control because of the new set of parts. IMO, by doing so, you ruined its collector value, but it sure plays a lot better.
Value is relative in my opinion, there’s always someone out there willing buy and there’s always someone who thinks the value of something is overpriced for what it is at base level. Even if there’s a general consensus of market price and rarity rating etc, Rare sticks are in the end just sticks too, its ‘rarity and value’ depends on the person who owns it in the end.
personally, I don’t simply mod if its a waste of time, regardless of what stick it is.