As some of you have pointed out above, the CFB championship is still "mythical", as this playoff is an invitational. It would be great if there were defined criteria to pick the playoff teams, but that has never been the case for CFB. I would love to see that change, but I doubt it will ever happen.
What we are really arguing about is who the last at-large team should be. We are talking about:
2-loss SMU (if they lose the ACC championship)
2-loss Boise State (if they lose the MWC championship)
2-loss Miami
3-loss Bama
3-loss Ole Miss
3-loss S Carolina
3-loss ASU or Iowa State (if they lose the Big 12 championship)
2-loss BYU
1-loss Army
Personally, I don't think any 3-loss team deserves a shot at a mythical national championship, no matter how hard their schedule is, and even if they win their conference. But we could get a 3-loss Clemson in this playoff, and we will likely get a 3-loss SEC team as the 12th seed. I guess that I can live with that, as this past November has been the greatest November of CFB in my memory. I wish CU had taken care of business against Kansas, but they didn't. At least they had a chance, and they controlled their own destiny into mid-November. So the 12-team playoff is an improvement, and there are some obvious changes that they can make to playoff seeding to make things even better.