Ohio State won as the #4 seed in a four-team playoff. Who's to say that the #5 team wouldn't have beaten them?
And that, folks, is the flaw in any college football playoff system. No matter how hard you try, you're never going to cover all the bases in a sport like football where it is impossible to compare teams across conferences because the season has so few games.
Yes you can - 10 conference champions - however each conference determines, 1 independent, and 5 at large. 16 teams, 4 weeks - 1 champion. That is unarguable, and even better than the basketball tournament because the regular season really, really matters.