I won't take any sides on the whole Bayonetta issue, mainly because I have very little experience playing vs her (out of the UAE's top 15 there is one Bayonetta). But I find it interesting from a game perspective.
@Nobie linked that article with the comparison between Bayonetta and Melee Fox, but I think it's less to do with those two characters themselves and more with the designs of their respective games. I don't want to open up a Melee vs Smash 4: Which is better? kind of discussion to add to the drama that we already have, I'll just try to be as objective as I can with my observations.
Someone pointed out that despite Bayonetta's popularity and presence, in-depth guides on how to defeat her are relatively sparse. I don't blame whining players for whining and not trying to adapt, because there's no denying that it goes back to this game's engine: Smash 4 is, from a tech skill standpoint, very shallow. That doesn't mean the game is worse than Melee: the two have very different design philosophies behind them, and both have their pros and cons. Melee offers such a vast array of movement and combo options, and while this probably makes it superior from a spectator standpoint, a price has to be paid: it's unforgiving. Personally I could not get into the game after multiple attempts, and I think the same holds true for a lot of low-level S4 players like me. Smash 4's design gives it an advantage (in one way) from a gameplay perspective, in that it promotes a greater focus on neutral and mind-games, since you don't need to spend as much time mastering complex inputs. The drawback here is it is not as entertaining to watch unless you have a deep understanding of the interactions going on. And the more limited design tech-wise means that is much more difficult to develop counterplay to dominant options.
With great options comes great responsibility--in a perfect world. Melee Fox has great options and is objectively the best character in the game, but it should be no secret that there is only one thing putting a cap on his potential: human limitations. I'll put it like this: Fox can beat everyone and everyone including Roy can beat Fox. But Bayonetta? The great options are there but I can't seem to find that "responsibility". But, hey, I won't dwell on this because there is nothing new to say about Bayonetta herself. I can't imagine a world where Melee Fox had a lower learning curve...oh wait, that did happen at one point. It was called PM Fox until they realized what a terrible mistake that was.
The effects of Melee's and Smash 4's differing game designs can be seen in their meta evolutions over the years. Melee had no patches (ignore the PAL version) yet there were some significant character shifts over the years: Sheik being #1 for many years before Fox usurped the throne, Ken totally changing perceptions towards Marth, Jigglypuff rising to the top-tier, and more recently Yoshi's rise thanks to amsa. Meanwhile, the vast majority of character developments in S4 can be contributed to patches: Meta Knight rising from low- to top-tier then falling to high-tier, Diddy going from best character to 9th on the first tier list, Marth and Mewtwo rising to top-tier, etc. There are a few exceptions, like Luigi rising back to relative prominence despite not receiving any changes after his last nerf, Megaman's surge in 2016, and Bayonetta (!!) falling off a bit after her 1.1.6 nerfs and then regaining ground some time later.
AFAIK, Brawl didn't see any notable decline until at least 2 years after release. It's fair to assume that despite such obvious problems as MK and Dedede chaingrabs being apparent from the get-go, the game still had novelty in that it was new and that maybe something would alter the course of the metagame. That never really happened as Brawl's meta stagnated and the few major shifts only made things worse (looking at you IC's). Sakurai has said in the past that S4 was designed to sit on the fence between Brawl and Melee, but that was just a marketing ploy to get disenchanted players to buy it; in reality, I'm sure we all know it's far closer to Brawl. And that makes for a sad reality, as by inheriting Brawl's DNA, S4 inherits its problems, which is only now apparent: until mid-2016 patches were always shaking things up, but with the meta all settled that novelty is gone. It's been 1.7 or so years since patches ended and it's safe to say S4 is now going through the same meta phases as Brawl. Only time will tell, though.
Melee's design gives a higher bar to entry, but those who make it through will stay with it longer. S4 is easier to play but I don't think it can keep your attention for as long. Which is better, overall? That depends on your perspective. In the second case, by the time a game is withering away, a new one is already in the making, and will grab the attention of many who left; if you're Nintendo, this is the better option. It's more profitable to make a new game than to support the scene of an existing one, considering most of the buyers are casuals. It's like planned obsolescence only maybe without the "planned". But as a gamer, whichever you prefer varies.
In conclusion, I don't care whether or not she is banned. I don't agree with either side because I believe that either way interest in the game is declining due to its core design flaws. Bayonetta may just be accelerating that decline. And I imagine banning her would lead to a small to moderate surge in entry and viewership numbers for a brief period, before that decline continues.