I wouldn't question Favors' motor. It may seem to people like he doesn't have the highest motor, but to me it seems like that's just his introverted personality (from what I've seen, which is really only games and interviews obviously). Remember that he did go to the coaches with specific things he wanted help with. It seems to me like he is always looking to improve and is willing to ask for help. Though the coaches should have been helping him with those things anyways. Corbin is worthless.
Hibbert seems to be introverted. Duncan also similarly. So it is possible to be introverted & at the same time be a "fighter" when the goings get tough.