Selecting the 4 playoff teams is much like selecting a prom date. It all depends on what you value. If you want a busty girl who will enable you to get lucky at the end of the night, you pick Cathy or Sue. If you want a future wife, you pick Cindy or Helen. If you want a gorgeous girl to impress your friends, you pick Kaley or Jill. If you want an athletic girl with rich parents, then you pick Marsha or Bev.
For the 4 team playoff if the committee wants the four teams with the most highly skilled players, then they pick Michigan, Alabama, Georgia, and Ohio State. If they want the 4 teams who performed the best against their schedule, then the pick Michigan, Washington, Florida State, and Texas. If they want a well rounded 4-team selection, then they pick Michigan, Washington, Alabama, and Georgia. It all depends on what the committee values and how much weight they put on the selection factors.