He'd be interesting as a fighter at least.
Honestly, I want more X-Men outside of Wolverine, Storm, Magneto and Sentinel, etc.
In terms of who I really played in the previous games, Wolverine, Storm, Deadpool and Magneto are high priority for me. Slightly lower than that is Rogue. I don't play Gambit, but I know he'd make people happy. Same with Psylocke. I do feel that most of the good X-Men characters have already been made fully playable in one entry or another. Although Nightcrawler, Havok and Mystique haven't had the the MvC treatment yet.
What I'm waiting for are more Spider-Man related characters. Aside from Spider-Man and Venom themselves. I mean Black Cat, Punisher(who should have been chosen over Bucky), Green Goblin, Carnage, Doc-Ock, Sandman and Scorpion could each have some interesting tricks up their sleeves to make them fun fighters. And that's just the well known characters, someone obscure like the Spot as one really neat gimmick that could be handled in interesting ways. Spider-Man 2099 would be fun too if they make him an Akuma type.
But I mean, I'm bias as Spider-Man and X-Men are and always will be my favorite Marvel IPs.
And of course, the best of them all, J. J. Jameson.
For Capcom, I'd like to see some Mega Man Battle Network. I'm not gonna complain, since the MMX series is my favorite, But MMBN has the best version of Bass. And it'd be great if one of these games lets us have a double Mega Man team. Especially if it's Mega Man X and EXE.