This was the exact same answer the guy from Activision's Iron Man/Hulk panel gave. (They never called on me on the q & a session, but I walked up at the end of the panel and quickly asked one of them) This leads me to believe that something is being worked on, but they don't want to make any claims until they are sure it will work.
The Activision panel also mentioned lots of comic book things added in, and the mention of the Baxter Building in that previous article seems to confirm that. (You can bet that will be my first destination when the game comes out!

)
One of the questions was about if there were any elements of "World War Hulk," and the answer was that yes, a p-o'ed Hulk would be rampaging through New York

, but no, there would be no Warbound or anything like that.
Someone else asked about skins, and they confirmed that Grey Hulk would be a skin, but were intentionally vague about Red Hulk. I think they were trying to gauge audience reaction to see if there was enough interest.