Leinart, the decision to bench him, and the timing of said benching.
If Whisenhunt states from the very beginning that this is an open QB competition, none of this drama is there. (well, there will be some there, but not the type and furor we are seeing now) Instead, he names Leinart the starter. He shot himself in the foot, ESPECIALLY if he had doubts about Leinart prior to this off-season. He could have given the same PC type response he is good at giving.
What team have you been watching the last 3 years???
Since when does anyone on this team have their position locked up just because they've been named the starter? If you don't perform Whiz isn't afraid to go another direction. Everyone knows that.