His script was a first draft of many done during the production. While Penn will always have credit for being the first to submit a script, it's obvious that Norton was writing from the perspective of a page one rewrite. I'm speaking from the stance of an aspiring screenwriter, so I have some bias. But I do feel that deserves some recognition.
As far as the issues with Universal go, I still think it's a natural part of the process. They seem to have streamlined his vision into something more action-oriented. There's no harm in that, especially for a Hulk reboot so soon after a massive critical and financial failure.