We can talk roster all day, but what kind of game would you guys want it to be?
I'd want it to be like a blend between Smash and a traditional 2D fighter. Basically Street Fighter with Smash's simplified controls where every attack is a direction plus a button. Three standard attack buttons and one special attack button. Up to jump and back to block. Make it faster than Street Fighter, but nowhere NEAR as chaotic as MvC.
I pretty much mentioned it before, but I really don't want any half step games. Capcom should focus on its strengths and do a traditional tag fighter that way you get to play up the personalities and potential of each move set to their absolute zenith. I definitely do agree that it should aim to be far away from what Marvel 3 turned into, but it should still focus on having good movement and a great sense of visual impact.