I think 8 teams would solve the issues enough and you can never avoid the next team down arguing they should have been in. You put in all Power 5 conference winners and the highest non-power 5 conference winner plus the 2 highest non conference winners. It might get a 2 loss Power 5 team left out occasionally to a 3 loss or so conference winner but would be the best way and keep the regular season very important. 16 teams is too long for college football.
Yeah, I think 8 teams would do the job. Take the 5 Power Conference champions, the highest ranked non-P5 team and then the next 2 highest ranked teams from wherever. Seed them and do it.