The SEC teams are beat up, from top to bottom it's the most physically demanding conference and every team lost almost half their starters over the year. When another conference comes along and wins 7 titles in 9 years, let me know.
I have no doubt at all USC would have taken down some of those SEC teams. USC used to schedule SEC teams and beat them.
2002: USC vs Auburn - W 2417 (9-4, 5-3 SEC)
2003: Auburn vs USC - W 23-0 (8-5, 5-3 SEC)
2005: Arkansas vs USC - W 7017 (4-7, 2-5 SEC)
2006: USC vs Arkansas - W 5014 (Arkansas 10-4, 7-1 in SEC)
Then the SEC stopped scheduling them. USC under Carroll would take on anyone, any place. In fact, USC has never played a D1-AA school, and SEC teams have 2-3 of those every year. USC under Carroll had 28-3 non conference record, and those 3 came in his first year. They did lose a National Title game to Texas, but watching that game I don't think anyone outside of Texas thought the Longhorns could do it again. Especially when USC shot themselves with plays like Bush running for 60 yards then lateraling to no one.
But anyways, at least with the playoff system we'll know whats up.
Although in all fairness, I would have said same about the Big 10 when they always got someone in (usually OSU), and the Big 12 (usually Oklahoma). Conferences get these reps of being better than they are from time to time. Even though the playoffs should be expanded a bit, the new system will force the eventual champion to earn their title.