Re: Changing the roster for Avengers 2?
I'd love Spider-Man to join, unfortunately that's never going to happen. It would be cool to have Nick Fury show up after the credits of the next movie, with Mark Ruffalo reprising his role as Banner. No Hulk, though.
Put the black costume in Amazing Spider-Man 3, use the crashed space shuttle for its origin. Introduce Jensen Ackles as Brock, the climax will have Spider-Man lose the symbiote in the tower, then post-credits we see Brock as Venom.