From various rumors, I think there will probably be a Captain America bike ride. Like Tron, just themed differently.
And then there was that Spiderman ride permit system people posted recently.
I do have to wonder exactly how much space they will end up using-if it will just be the backstage parking lot, if it will include part of Bugs Land (I hope not, as I think that land is adorable and provides some much needed childrens rides for DCA), if it will include part of the Hollywood Blvd area (Hyperion Bay, Monsters inc). I wouldn't have thought they would have gotten rid of the Hyperion, but also didn't expect them to demo half of Downtown Disney for a new hotel, so who knows whats in store!