I've always been a fan of going back to computer rankings and expanding the playoff to 6. 5 conference champions* (*must also be ranked in top 10...aka no 3 loss conference champ gets a shot at a playoff spot) and the other open spot(s) go to first teams out.
Last year USC wouldn't qualify but Clemson, Bama, OSU, and Okla all won their respective conferences and were in the top 10. ND and A&M were first two out so they'd get in.
Once you know the 6 contenders, they get re-ranked w/ first two getting bye.
I think I saw this scenario suggested last year: Bama (1) and Clemson (2) get a bye. Oklahoma (6) vs OSU (3) and ND (4) vs A&M (5). Had USC qualified, it would've bumped A&M and it would've been a USC vs ND matchup to get into the Final Four.
Personally, I'd be in favor of this. It rewards the conference champs (but penalizes the weaker conferences; aka no 3 loss conf champ is getting in). It at least opens the door for at least one other team to play itself in. Honestly, I'd be fine if they pushed it to 8 teams and still did this scenario. But beyond 8, I feel like those teams don't deserve a shot....they either have multiple losses and/or didn't win their conference. It should be that simple.