What's on another level is how over nerfed Bayonetta was. Not how players react
Whats worrying is that this is the trend now. See: MK, ZSS. Who's next?
I'd argue that Meta Knight and ZSS along with Diddy, Luigi, Sheik, and even Bowser -- remember how his U-throw was re-tuned? --weren't "over nerfed" like how Bayonetta was. What they could do, they can still do, but in a much, much toned down way. They kept something. Call it a game plan, a tool, a style, or a niche. Whatever they had that was very powerful, was kept, but toned down -- re-tuned if you want to be nice or if you want to be blunt, nerfed in a way that they still kept a part of their identity. Bayonetta didn't. What she had wasn't toned down. What she had wasn't reduced in "range" like how Luigi can still use D-throw to setup his "Luigi combos", his "Luigi thing", but within a stricter range where he can't combo whenever and also setup for KO percents at the same time. What Bayonetta had was a nerf that damaged, removed, a part her identity. She can combo, but it's just not like how she combos anymore, especially when 2 of her prominent setups and followups are made to be unreliable. They could have been re-tuned to have stricter ranges, but they were not. They were made to not be things that say, "Bayonetta". She lost something that defined her, her niche.
Without a niche, there's really no point in playing a character other than for the character itself. Take Marth. Unrewarded for his spacing, the mechanic he was based around on. When characters who space normally or even sloppily, but get rewarded just as much or even more than Marth, what's the point of Marth? People play Marth for his tippers; for that something that nobody else has. That was Marth from his transition from Brawl to Smash 4. Marth now? Holy ****, he is fun to play because his tippers do something; his niche does something. It's defining, it's satisfying, and it's just Marth. Before that, absolutely frustrating. You'd do everything in your power to play Marth, but people would just outdo him. You'd try to make up shortcomings by working on areas Marth is capable of, but does not excel in. Marth can edgeguard, but that's not his specialty. That's not his shtick. Edgeguarding would go to someone like Jigglypuff or the Pits. You end up spreading Marth thin.
Annnnd... I just reiterated what Emblem Lord just said a few posts after yours. Sorry, Emblem Lord, I didn't want to steal your thunder. I just write and stuff comes out of my head.
Rosa. She's the only character I can see that the devs would nerf to the extent of mk/zss nerfs. Maybe cloud as well.
That happened in 1.0.4. Greninja also was a recipient. Key thing here: they didn't lose their niche. Rosalina's still a defensive wall and Greninja's still this ambush, "ninja character". They're just not that crazy anymore even if Rosalina is that crazy for some people.
I do feel balance is overrated, but Brawl's metagame was in shambles and MK/IC's being completely borked was part of it. My issue with Smash 4 is everyone getting weaker. It's why I get hype for Mewtwo because he gets stronger and stronger, the way I feel patch cycles should be.
I feel like people, and I'm not exempt from this, are confusing balance with something... I feel like what people think of balance is where there's no bad MUs, everyone has access to all tools, and that it's all about skill. That ends up making a really boring game. It becomes monotonous when there nothing crazy happening. And I think this comes from the fact that Melee and Brawl were extremely imbalanced. Hypocritically, people ask for over-tuned and broken tools while asking for those that aren't on their characters to be nerfed severely without regard to what defines the character, but that's another story.
Anyway, what I think people "want" is a game where people are on "equal" footing. Going to be difficult to word this, but it'd be a game where there are bad, but not severely bad, borderline unwinnable MUs; there would be common tools characters have access to, but characters specialize in them differently e.g. everyone can anti-air, but some characters have much more potent or reliable anti-airs; and that there is a focus on skill -- why wouldn't there be? --, but MUs do have an affect e.g. you can't expect say, a grappler to not have trouble against a zoner. As there's imbalance, you end up with a game where things are never the same e.g. where it's never jack of all trades who happens to be kind of a rushdown vs. jack of all trades who happens to be kind of a zoner. Basically, it's never Mario vs. Mario or Mario vs. Pit. It's something like Fox vs. Marth or Sheik vs. Bowser. It'd be unpredictable and exciting since you'd never know. That suspense is what makes it fun