Phish--
Part of the problem is that some teams play in weak conferences. Can you honestly tell me that you think that Boise State if they are the only other undefeated team should play Ohio State in the National Championship Game?? (saying that Ohio State goes undefeated also).
The problem is a multifaceted one that does not have as simple an answer as what you desire (playoff system). If they go to a playoff, how will you decide who is in and who is out? Additionally, a playoff system does not determine who the best team is, only who is peaking at the right time and is able to win x number of games in a row. Billy Donovan of Florida even commented that Florida was not in his opinion the best team in Basketball last season, and that if they had been a different seed or in a different region, they probably may not be National Champions right now!