I'm confused. Are you saying you don't have any reasons why a playoff system would be worse, or why it would be better?
Also, one difference between March Madness and a football playoff is that a football playoff would take place over top of two holidays, and/or final exams. Granted, the bowls do too, but that's for only one game. (Me, I don't see this as a problem, but that's the difference for you. Also, half the teams in March Madness are kaputski before the weekend even begins - football playoffs would probably be all Saturdays.)