Here's a fun Bayonetta rant for you gorls :^)
Bayonetta never has never been the best character in the game, and due to the nerfs, never will be. However, that's not to say that she wasn't one of the strongest characters, because that much is undeniable.
Her biggest claim to fame was being an extremely potent character who was easy to pick up and win with. Despite that, Sheik was absolutely a better character in 1.1.4, and I'd argue Diddy was also better than Bayo in both 1.1.4 and 1.1.5. Bayonetta saw so much usage because she was much easier to do well with than characters like Sheik who require much more effort and skill to play optimally. That's why largely irrelevant players such as Tyroy and 9B were suddenly able to make a huge splash on the scene. Bayonetta's situation was analogous to 1.0.0 Rosalina's. Rosalina was overtuned and everyone considered her the best character in the game. Everyone was playing her, and she was taking tournaments left and right (which didn't really happen with Bayo, but she did get tons of high placements in many tournaments). However, lurking in the shadows was pre-patch Diddy, whose potential was yet undiscovered, but still greater. Then people figured out what Diddy was capable of and Rosalina was figuratively thrown by the wayside due to her bad Diddy MU.
Pre-nerf Bayonetta also thrived off of the fact that she was so new. Had she been in the initial roster, she would have been figured out and the general playerbase would know how to combat her. Being released a year and a half after the game's launch meant Bayonetta could essentially get away with basically whatever she wanted because no one knew how to counter her (and this is still largely true today; most people still don't know how to effectively fight Bayonetta).
The instant stigma attached to Bayonetta and those who played her only compounded that fact. She was labeled as toxic and top players said she was ruining the game, so the masses ignored her and just waited for the nerfs. They didn't want to put in the work and learn how to beat her, so even when videos and guides were made by community leaders (ESAM showing that SDI can consistently escape Bayonetta's 0-deaths, Beefy Smash Doods creating a video on how to optimally DI and combat Bayonetta's set-ups, etc.), they were ignored in favor of crying about Bayonetta's "toxicity" and destruction of Smash Bros.
To get real here, Bayonetta mains were targeted and attacked by the general Smash community. Other playerbases have also experienced hatred and "discrimination" (Pre-patch Diddy players mostly, but Sheik mains have always gotten **** about playing a top tier), but it was never to the extent of what happened to Bayonetta mains. People would invade her subforum, create multiple threads, hijack threads, just to say that she's broken, she's ruining the game, all Bayonetta mains have no skill because they play a broken character, etc. It got to the point where any time Bayonetta was mentioned, you could be sure to expect multiple posts about how she should be nerfed to the ground/removed from the game, etc. That's coming from my experience here on SWF; I fear to think about what GameFaqs and Reddit was like regarding Bayonetta. Bayonetta mains still get hate (although not to the same degree), which just goes to show that the stigma still persists. Bayonetta was regarded as toxic, but the only toxicity was those who were so vehemently against her.
Also, Bayonetta did have losing MUs pre-patch. Diddy was definitely bad (it still is), and most of the projectile characters were not good for Bayo either. She doesn't really have a good answer to smart projectile usage. Heel Slide is too slow, predictable, and punishable. Bat Within is too laggy to use as an approach, Bullet Climax's angle means it misses on most characters, and Bullet Arts moves (such as dtilt and jab1) are not great for forcing approached due to their range forcing you to sit still and fire bullets at a range where most characters can punish you. Bayonetta could try to jump over the projectiles and try to punish with a dABK, but that's pretty predictable. Witch Time is possible, but you have to be really close to the opponent to slow them down. Powershielding obviously exists, but you're not going to be able to powershield all projectiles 100% of the time. But none of that ever came to fruition because no one understood that playing patient did not mean "wait for a while and then blindly dash at Bayonetta from across the stage, so she has all the time in the world to figure out how to punish you."
I'm not trying to down play the fact that Bayonetta's 0-deaths were stupid or that she was a strong character or her nerfs were undeserved, but she wasn't best in the game.
tl;dr Bayonetta has never been the best character and she was nerf-bombed because no one wanted to put in the work to learn how to fight her. Like, they only needed to nerf dABK and her 0-deaths would have been gone, but w/e ¯\_(ツ)_/¯
