Idk that they've really announced much of anything yet, but what people were saying on twitter was:
PAC-12 and B1G drop a conference game. So it'd be 1 ACC, 1 PAC, and then two G5 non-con games. Theoretically you could still schedule an SEC game, but why would you unless it's something like GA Tech and UGA (and I'm sure they would have to figure something out w/ that rotation).
I think more than anything this is about reducing ESPN's power in pushing the movement for the sport for TV revenue. If the playoff is reconfigured before the contract ends, you're stuck with ESPN coverage for the extended term of the deal. Alliance members have made it clear they're not going to approve the new playoff without some changes, and my guess is that means that you try to negotiate that rights picture with NBC/CBS/Fox and see what a competitive price looks like.