My personal #1 would be; ND & UCONN.
The Domer cry would be glorious, and I think that would effectively end B1G expansion forever. As stated, moves that destabilize the BXII (KU) or ACC (UVA, etc) would only lead to MORE schools. 18, 20, etc etc. I'd like to avoid that.
If ND will truly never EVER EEEEVER come, then KU & UCONN would be #2, so #1 for this poll.
I've decided (((in this hypothetical universe of CR lunacy))) that if the B1G MUST go to 18 I'd rather it be UCONN > KU > OU > TX. ACC needs to stay in-tact, IMO. Let ND keep their d-ick in the tail-pipe and never fully join. Screw UNC and UVA. I'd much rather have TX & OU. Two all-time great FBall blue-bloods, and UCONN and KU bring the hoops. I'm done with the schools only added for eyeballs. I'd like some power ala NEB/PSU additions.
If the B1G ends up in GA with GT and FL with Free $hoes U., I'm quitting the tronz.
Seriously tho, imagine a B1G that's 'western front' runs from NEB > KU > OU > TX. Talk about "regionalizing" a Conference. The SEC would be completely surrounded by the B1G, with nowhere else to go as the ACC has been fortified. TX would be the only split state, unless they took ISU, OKST, KSU, etc etc., but they are much poorer little brothers. I guess I could see OKST going SEC, not sure about others. We would totally engulf them.
TX and up thru the Plains States, Midwest/Great Lakes, Northeast, NYC and Mid-Atlantic. Pwn3d.