https://sports.yahoo.com/why-college-football-playoff-seeding-format-is-...

Apparently, to change the way teams are seeded and awarded byes requires a unanimous vote by the conferences. 

The SEC and Big Ten want to change the way byes are determined so that we don't end up with Boise State and Arizona State (two lower ranked teams) as the #3 and #4 seeds again like this year.

Of course, the other conferences like things just the way they are as they feel that the Big Ten and SEC would probably grab the four top spots if using only the final CFP ranking.

It will be interesting to see if anything does change this off-season.