My theory is this ..
Rooney is like certain sportsmen (John McEnroe was another) in that he is at his best when he is pumped up with aggression. If you take that out of his game he is half the player, or less. In this tournament, he was banned for the first 2 games and I suspect was subsequently told by Hodgson to watch himself. He has a reputation, opponents, referees and the watching world would be aware of it, and he had to mind his manners, so to speak. You could clearly see he was restraining himself, avoiding tackles, avoiding any argy bargy and avoiding confronting refs, as he loves to do. He has an angry side to him and when he lets it out that other side comes out of him too, that side of him that is one fantastic player. At international level, far more than in the Prem, physical challenges and dissent are not tolerated. In the Prem, playing for Man Utd, he can more or less do as he wants without any punishment. He kicks people, he elbows people, he runs fifty yards to get in the ref's face, and no-one bats an eyelid, least of all the media. For me, this is why he is far less effective for England, and in the CL for that matter. Rooney is a brilliant player in the Prem, his form dips sometimes but overall, I would say, he is the Prem's outstanding performer.