This is just a theory, but I think Terrell Owens and his huge shadow being in Dallas isn't good for Roy Williams.
Owens is such a forceful, dominant personality, that Williams seems content to slack off, run a few routes as the No. 2 guy and just enjoy the circus. Of course, he'll whine a little bit, because in this day and age, that's almost what is expected of receivers.
If Owens is gone, and the coaches sit Williams down and give him a "come to Jesus talk," telling him that the franchise gave up a lot for him, that he is critical to the team's success, that he needs to assert himself as the No. 1 receiver, then I think he might come around and accept the challenge. Austin would be a nice No. 2 to go along with Williams and Crayton could remain the slot receiver, where he's best suited.
But if Owens stays, I see Williams' personality as someone who will just do enough to get by and let Owens continue with all the drama and be the No. 1 guy. Like it or not, I think Williams needs to be built up, prodded and told he's the No. 1 guy for him to be able to really excel in this environment. That can't happen with Owens here.