The roster will include several members of the Avengers. Each character/hero will even have a skill tree of their own (rpg elements). Hope that bit of info helps!
I think it's safe to say that whatever this project is, it's definitely a next-gen thing and not a current-gen thing.
Either way, a fully-fledged single-player driven AAA Avengers game is exactly what we need right now in the wake of Insomniac's excellent Spider-Man outing that paves a way to an Avengers universe.