I think that the Big 12, version 3, will be OK. It will gain Cincinnati, which will have one more CFP appearance than the rest of the conference has.
Re Lincoln Riley at USC, I don't know if he's the guy as HFC to take a program on the skids and rebuild it. He hasn't demonstrated--hasn't had to demonstrate--that skill yet.
In taking over at OU in 2017, he got handed the keys to a Corvette. He leaves it in 2021 running not as well as it did when he got it. In fact, each year since his first one, it has run slightly worse than it did the year before, and the trend seems to have been accelerating. CFP loss in OT; 11-point CFP loss; blowout CFP loss; non-CFP Sugar Bowl champs; non-Big 12 champs.
How well he'll do with a car with an engine that hasn't been run in several years will be an interesting thing to watch.