There have been many rumours that Phil Coulson will return as Vision. If these aren't true then I'll go take a long nap and try to forget that Phil is dead... forever... and is never coming back.
They are already adding more heroes to the Marvel Cinematic Universe, like Ant-Man and the Guardians of the Galaxy (I really don't see how the Guardians of the Galaxy are going to be part of it).
I hope that Sony and Disney will be able to join forces so that Spider-Man can be an Avenger in the films too and not just the comics. He should be played by The Amazing Spider-Man actor, Andrew Garfield so that it can connect to that series.