Kill me if you guys want to, but I actually kind of like Corrin and Bayonetta. I've been warming up to them quickly over time.
As soon as I first saw Corrin, I went like "...Who?", but now that I've taken to time to properly look at him, he seems to bring a lot to the table, and he looks like an interesting character. As for Fire Emblem being overrepresented, well... I made this little thing here on Notepad, showing how many series this game has and how many reps are in each series. The end result was this: (Please correct me if I'm wrong, I actually did this all by head)
1. Mario: 10 (Mario, Luigi, Peach, Bowser, Yoshi, Rosalina, Baby Bowser, Wario, Donkey Kong, Doctor Mario)
2. Pokemon: 6 (Pikachu, Charizard, Jigglypuff, Greninja, Lucario, Mewtwo)
3. Fire Emblem: 6 (Marth, Roy, Lucina, Ike, Robin, Corrin)
4. Zelda: 5 (Link, Toon Link, Zelda, Sheik, Ganondorf)
5. Kirby: 3 (Kirby, Dedede, Meta Knight)
6. Wii: 3 (Mii Gunner, Swordfighter, Brawler) (Counting them just because they might be relevant)
7. Kid Icarus: 3 (Pit, Palutena, Dark Pit)
8. Donkey Kong: 2 (DK, Diddy Kong) (Maybe you can count Mario?)
9. Metroid: 2 (Samus, ZSS)
10. Pikmin: 2 (Olimar, Alph)
11. Star Fox: 2 (Fox, Falco)
The rest only have one rep per series (Captain Falcon is the only one representing F-Zero, Little Mac is the only one representing Punch-Out, Mr. Game and Watch is the only one representing the Game & Watch, you get it)
However, if you count absolutely everyone that has ever been in this series...
Pokemon lost 3 representants, Pichu, Ivysaur and Squirtle, which would leave them with 9.
Zelda lost 1 representant, Young Link, which would leave them with 6.
Star Fox lost 1 representant, Wolf, which would leave them with 3.
So, in conclusion, if you look at the whole picture, then Fire Emblem is tied in 3rd place for representation with Zelda, with Pokemon far ahead with 9 and Mario just winning with 10. So, is Fire Emblem overrepresented? ...Maybe just a bit, I don't know, but I will say this: If you see someone happy that we got another Fire Emblem character... don't rain on their parade. It'll do nothing but make you look like a salty arsehole. You can express your disappointment, sure, of course, but don't try to demonize the people that actually liked Corrin's inclusion.
Okay, enough about Fire Emblem. Bayonetta!
She's cool she looks pretty she looks interesting I kinda like her the end. That's all I have to say about her, really.