Because 1 not all conferences have them, 2 by the end of the year you have a ranking system updated every week, either it's right or it's not. You either have a ranking system or you have an NFL type system with no rankings. In the case of the later you would need conference championships. As far as 16 teams goes there really is not time for it, the schools already protest 8.
Say what? How can they protest something they haven't got?