No. Just... no.
I like Kingdom Hearts and I like Marvel, but the two do not go together. Maybe, MAYBE Spider-Man, if you used his classic old show/newspaper comic persona, but I don't see anyone else fitting into the game. There is a clear light-heartedness and charm to the Disney elements of the series that the Marvel properties just don't have today. Plus, all the Disney worlds share one thing in common: they are original Disney properties. Which is probably why you also won't be likely to see a Pixar movie be used as a world.
Though if they did opt for Pixar, Toy Story, A Bug's Life, Monsters Inc., The Incredibles, and WALL-E would all make awesome worlds.