“I can’t say that it’s entirely out of the realm of possibility, ” says project director Masahiro Sakurai and an interview with IGN. He goes on to state that while there is a chance that Capcom characters could be included in the next Smash Bros, they would have to fit in with the universe that is forged by Nintendo characters. To be honest, it doesn’t make too much sense since that didn’t stop Snake from being included, and he arguably the most out of place character in the game (but still awesome though). But, we’ll just have to wait and see.
Iwata revealed during the E3 press conference that the next Smash Bros. we be made for both the 3DS and Wii U and that the two versions will work together in some way. So far, development hasn’t started yet, but Sakurai and Project Sora are looking for people and developers to help in making the game. No release has been set (obviously)