To be honest, I think MVC, at least, the newer games that weren't just sprite dumps, also mostly adhere to the "main character / mascot first" rule. At least for the Capcom side, which Capcom obviously has full control over.
Like really, outside of Mega Man being a complete no show in U/MVC3, there isn't anything egregious feeling about the Capcom side. Basically all of the other series represented have their main character or poster boy/girl there, like Ryu, Frank West, Arthur, Chris, Viewtiful Joe, Morrigan, Ammy, Dante and so on.
It's only the Marvel side that's a little weird, like Rocket Raccoon but no Starlord or Doom/Super Skrull but no Fantastic Four, but that was mostly selected by Marvel anyways.