I've always felt that USCs biggest enemy is the weak competition in the Pac10-12. Sure they have to compete with Oregon, and I agree Oregon looks better, but they hold their destiny in their own hands with Oregon as they play them, and if they beat them they should get to the NC game.
But not having to look sharp, because there is not another team in your division that can prevent you from even getting to the division crown, and sometimes not even a team in the other division that can make you feel the need to play your best is a disadvantage IMO. Even back in the days of Pete Carroll. How can you prepare for teams that really are at your level, when you never face it over the course of your season. IMO, there's no reason they shouldn't have a high profile game scheduled out of conference (other than ND, who has sucked for 15 yrs).