That's probably why I've never complained about obscure characters being added to the fray.
Marrow, Silver Samurai, Spiral, Sentinel, Blackheart, Shuma Gorath, or Omega Red (arguable). All of these aren't that popular, but MAN, did some of them make good movesets.
I adore X-Men: Children of the Atom, but the character selection confused the shit out of me. In the 90s, the X-Men members made sense (save for the lack of inclusion of Jean, Gambit, or Rogue, the last two were remedied later), but the villains? The main villain was Magneto, so you'd expect members of the Brotherhood like Sabertooth, Mystique, Pyro, or several others. Nope. Silver Samurai, Spiral, Sentinel, and Omega Red. All of them having little to no connection with Magneto. Juggernaut made sense though.
But damn, were the four of them fun. And as you can see, people don't want to quit Sentinel.
Capcom has always been strange with their character selection. Marvel Super Heroes including Psylocke as a Marvel rep amongst the biggest Avengers, Wolverine, and Spiderman. I adore Psylocke, but that's never made any sense.
Regardless, I'm not going to complain about character inclusions as much as I'm going to have issues with their potential movesets. The mention of Rocket Raccoon being a Cable clone worried me, but if anything, he's far more of a Trish + Chris combination, and I'm liking that.