I've been reading about this on Empire. It seems he might not have played nice with Marvel in the past, so they've done the dirty. On the other hand, I think the Avengers is doomed with too many characters and stars. Of all of them, Norton was probably the most replaceable, so hopefully they'll reduce the role too. If the story is as I heard, a sort of team up to catch The Hulk, then it will be better if Big Greenie is little more than a shadow so far as the plot is concerned. No need to flesh him out.