The X-Men can kick rocks at this point for all I care. Marvel is spiting Fox everywhere else concerning them so it would be a surprise to see any of them appear, even the iconic Wolverine. It's fine really, there are plenty of great characters in the MCU that deserve a chance to shine in the next big crossover and provide originality and new gameplay styles. I'm biased though, none of the X-Men I wanted showed up in MVC3 (Cyclops, Gambit, Iceman, Bishop, Quicksilver, etc) so I don't really care about the rest of them.

Use the MCU with a wildcard or two and the Marvel side will be fine. Throw in Quicksilver and Scarlet Witch I'll say. That's a little bit of a spite to Fox and we still technically get a couple X-Men comic characters.

For Capcom, just don't stuff the roster full of the same characters we've been playing for the past 10-20 years. They did pretty good last time so they should mix some things up. Ryu and Chun Li are mandatory. Throw in a SF3 or SF5 character, Laura or Rashid and maybe throw in Nash for VS series nostalgia.

For Darkstalkers let Morrigan and Felicia take a nap and give us Jon Talbain and Demitri. For RE we've had Chris, Wesker and Jill so let RE1 have a break and swap them out for Leon and Clare, maybe Regina instead of Clare for nostalgia. Swap out Nemesis with Tyrant or get rid of him altogether. This is a new MVC4 which means the same roster, even the newer characters shouldn't be copypasted and other characters should be given a chance to shine. Don't care about Spencer so he can stay or go.

Now for personal wants, I want Hayato more than anyone else to finally come back to MVC. He's my #1 pick. Other than that some classics like Jin and Captain Commando would be great, but the Capcom roster is so stuffed now I don't see where they would fit in. There are simply too many Capcom characters to use. They really need to just make a VS style game with all Capcom characters, people would eat it up. 50 Capcom characters from dozens of different IPs? Instant buy, but that's a convo for another time.

And oh yeah, don't snub Megaman this time. Zero is my favorite MM character, but that was just insulting. My personal pick is X, but Volnutt or even EXE would be pretty good choices. Classic is passe. Oh and Roll for the lulz. Make her a top tier character too just to troll.

Maybe let one of the DMC characters sit this out and also give Viewtiful Joe a rest and give us a Monster Hunter character or two.