The moment where I was enlightened to how toxic the Smash fanbase is, was when Hero was revealed in the E3 livestream and the video got bombarded with dislikes. After Banjo got revealed, the dislikes instantly faded away. You literally can't win with the fanbase unless you give them exactly what they want, (really the only exception to this was Joker, but I'm pretty sure if Joker was seen as feasible by most people then he would have done pretty well in polls). Also obviously the whole Grinch leak fiasco.
Literally every reveal nowadays is seen as meh unless it's an extremely popular character that the fanbase wants/has wanted for a long time ie. Geno, Sora, Dante, 2B, Phoenix Wright, Crash, Chief etc. "Left field", characters are viewed with a lot of toxicity and it takes weeks for the community to get over it (and this is even outside of Byleth). Seriously, we're 70+ characters in, and people still act like some tragedy happens when just one of the new characters isn't the exact character they wanted.
It's a miracle that Sakurai and the Bamco team has the mental strength to drudge through Smash enough for a second fighters pass, considering how much toxicity the general fandom throws at them after every "non-requested" reveal. I'm pretty sure Sakurai has admitted that he avoids talking about games he likes on twitter now, because people will just take anything that Sakurai likes as a huge point for them getting into Smash. And it's pretty clear that Harada hates people that only look forward to the next big reveals, considering all the nice things he had to say to Smash fans on twitter.