Ghosty! Also, Machine Man would be sweet as Hell, Krpy! Dr. Wily would be an odd one. Course, he built Zero. Not sure how deep they're getting into each one's stories though.
Tons of mutants to choose from Marvel, but they take a lot of the roster as is. Not saying I would mind it. But, hrm, let's see...with Super-Skrull and Doom in the mix, I'm pretty sure we can bet on a FF member. But who knows. Would make sense to have Richard's in there. Since the plot is dealing with the T-Virus and the science-y plot. Maybe Zombie Mr. Fantastic could be an alt costume! And I'm still convinced there'll be other costumes, and maybe hidden characters behind certain fighters. I'm hopeful. Sue me.
As for Capcom--Mega Man. I mean, Zero is the future of MM's universe and Tron Bonne is way in the future, but they have to have Rock. 9 and 10 are big editions to PSN & XBL. Plus, with Mega Man Universe coming out for DLC, they'll most likely put him in there. Almost positive. He's technically Capcom's mascot. Maybe not as show-boated now, but he was their first big character. (Also, where the heck is Strider? He was in the 1st two MvC games.)
What happened to Frank West? Rumor? I forget and am too lazy to go back in the thread. Also, looking at Samanosuke Akechi from the Onimusha series.