Not sure expanding necessarily leads to more opt outs. Especially, if you can expand the playoffs and only add a game or two over the existing schedule. Still having a chance at the Natty is pretty good incentive under the current scheme. I'm not aware of anyone from Cincinnati, Michigan, UGA or Bama that opted out, including many who are projected to high in the first round. Drop an out of conference game and add 1 to the current format or drop an in conference and an out of conference and keep the same number. I would put the caveat in that once you opt out you're opted out for the rest of the year. You don't play in quarter/semi-finals, you don't get to play for the ring.
I think it will reduce opt outs, they are all opting out of meaningless games, no one has ever opted out of a playoff game or regular season game for a team in contention for the playoffs. End of the day kids want to play in meaningful games, they are opting out because their teams are not good enough to make the playoffs.