Why's that? If the BCS Championship was set with TX and FL, then no one would care if either BSU went undefeated or TCU went undefeated or both of them did. Throw in an undefeated Cincy and you still probably wouldn't get anyone terribly upset. All the undefeated mid-majors in the world (sorry, Big East, you suck) won't matter to anyone if there are 2 dominant, undefeated teams from the majors.
IMHO, only an undefeated Iowa would cause serious problems, considering that would include wins over OSU and Penn State. The computers could very well have them 1st or 2nd.