You are giving way too much credit that the committee will be completely unbiased when it comes to playoff selection. There is a reason they are using a committee (vs unbiased computer rankings) and a loose goal of "the 12 best teams". They can change the goal posts to get teams from certain conferences by changing from SOS, eye test, head to head, etc as needed so the Big Ten and SEC get their 4+ number. The SEC and Big Ten will get their 4, Big 12 should get 2 but they will find a way to get that down to 1, ACC will probably get 2 just because they still have traditional "blue bloods" in the conference. And that leaves the best Group of 5 team.
I hope I am wrong but the CFP committee has never made sense in the past except they are trying to get certain teams in. Now it will be certain conferences for the at large spots.