4 conferences of 16; 4 conference winners in the playoff. That creates a de facto 8-team playoff with the conference championships, based solely on objective conference standings rather than subjective rankings. Let the AP rankings determine the playoff seeding.
Dissolve the Big 12, with 4 of the 6 Texas and Oklahoma teams to the PAC and 2 to the SEC; Iowa State and the 2 Kansas teams to the Big 16; and WV to the ACC. Then Notre Dame should join the ACC, but that leaves us with 65, so Notre Dame should have to hold an auction to buy their way into the P4 (lowest bidder wins). But preferably, the Big 16 should just give Rutgers the boot; they don't belong. This will be Division 1.
The current group of 5 should become Division 2 and create their own playoff, so that UCF, Boise, and whoever else comes along can actually win a championship that nobody cares about. FCS becomes division 3, D2 becomes D4, and so forth.
10 conference games for all of the P4. Only allowed to play up or down 1 Division at most (so no more FCS for P4 teams). But I think most teams will be using one of their OOC on a rival like Oklahoma/Texas if they don't end up in the same conference, and the other OOC as a tune up game.
7 of your 10 conference games is of course within your division, with 2 cross-divisional games alternating, and 1 based on where you placed the prior season (1 vs 1, 2 vs 2, etc.) Alabama/Tenn and Auburn/UGA will be preserved by moving the Alabama teams to the East, and moving Missouri and the two new additions to the West (the SEC will then make sense geographically). SEC Championship game to rotate between Atlanta and New Orleans or some other major city located within the Western Division. The other conferences can realign as they see fit.