My unified theory for P2 realignment as it sits right now:
There are 6 programs left that add value to the B1G or SEC: Notre Dame, UVA, UNC, Clemson, FSU, Miami, with Miami being the least of these.
That leads to 2 probable scenarios for realignment:
Scenario 1: SEC chaos
Notre Dame, UVA, UNC -> B1G
Clemson, FSU, Miami -> SEC
The rumored 4th candidate here for the B1G is Stanford. Builds out west coast, rival for Notre Dame, fantastic academics.
The chaos is the SEC has no obvious 4th candidate. One lucky, undeserving school gets a free ticket to P2. Who will it be? Your guess is better than mine.
Scenario 2: B1G chaos
UVA, UNC, Clemson, FSU -> SEC
In this scenario Notre Dame is still an obvious take for the B1G, but is Miami? They're on an island, and borderline for adding enough value to begin with. Maybe the B1G adds Stanford, UO, and UW instead.
There are other possibilities of course, but I see these two as the most likely.