"It’s literally the Promethean myth. I laid out a two-film thing: The origin and then the idea of Hulk as the conscious dreamer, the guy who can handle the trip. And they were like, ‘That’s what we want!’ As it turned out, that wasn’t what they wanted."
Norton goes on to say that he and Kevin Fiege got along great but what the two of them wanted were on two different tonal and thematic levels and Norton did not want to spend time working on Fiege's vision.
Fiege took a swipe at Norton when hiring Mark Ruffalo to replace him, stating the decision was based on needing someone who had a creative and collabortive spirit. Norton thought it was a cheap shot, but again maintains that no fighting occurred on set.
Hulk has yet to be given another film and there have been no suggestions made one will be coming in the future.