Just remembered where I heard this concept, but it was Chip Paterson on the cover 3 podcast. Re-listened to it earlier today, and I agree with these two points.
1. 16-18 team conferences are insane (prob swells more than that), and tie-breakers with that many teams would lead to a lot of what ifs. Best way to solve that is a semi-final. Also, imagine a hypothetical last year game where Oklahoma State beat Texas and made the playoffs. I'm 100% certain they would get waxed once they got in, but it would make that game interesting, and there would be a lot more at stake for the underdog. Conference championships would mean something, teams are not resting starters, more $$$ to pass around the conference for a better TV product. Lot of upside. With that said...
2. Would only be interesting if auto bids for conference champs are still a thing. Get rid of auto bids, or expand the playoffs any further, then forget it.