Even if Ohio State loses to USC, it's very possible they'll get back into the BCS Title game; the SEC and Big 12 champ will very easily have one loss.
I agree, though my reasons have everything to do with OSU getting more respect than they deserve. Look at the Big 10 competition...Illinois, Wisconson, Michigan... none of these teams are anything special. If Ohio State makes it back to the title, they will lose to Florida, or Georgia, or LSU.
Wisconsin is a preseason top 10 team. Penn State (which you didn't mention) is #13. Illinois is coming off a Rose Bowl appearance. Michigan kinda sucks, but their rivalry game is always big.