However, it wouldn't be my choice since it has a higher risk of limiting rivalry games and could turn people off on who is in what division in a given year. Regardless if the ACC does 2 divisions or 4 divisions it would still need to decide whether the pods/divisions would be regionally based or zipper model based.

Regionally Based would probably look something like this:

Pod A: Clemson, FSU, GT, Miami
Pod B: Duke, UNC, NC State, Wake
Pod C: L'ville, UVA, VT, 1 more
Pod D: BC, Pitt, Syracuse, 1 more

If the ACC sticks with 2 divisions and 2 rotating pods, then Pod A would probably be paired with Pod D and Pod B paired with Pod C because UNC-UVA rivalry trumps Clemson-NC State and Miami-VT rivalries. The protected Pod B-Pod C pairings could look something like this:

UNC-UVA (South's Oldest Rivalry is a must annual conference game)
Duke-??? or L'ville *may depend on if the ACC wants to pair the bball schools together or not
NC State-L'ville or VT
Wake-VT or ???

The bad thing about regionally based pods/divisions is that some teams won't have equal access to NC or SC/GT/FL every year.

The zipper model would be tougher to do with 2 division/2 rotating pods and still be able to appease most people. Assume Pod A is paired with Pod B and Pod C is Paired with Pod D, then the 2 division format could look like this:

Pod A: Duke, L'vile, Syracuse, Miami
Pod B: Wake, Pitt, BC, FSU
Pod C: UNC, UVA, GT, 1 more
Pod D: NC State, VT, Clemson, 1 more

In this scenario UNC would have to decide between preserving its rivalry with Duke or NC State. Most likely though if the ACC is doing the rotating pods then it would look like this:

Pod A: Duke, UNC, UVA, GT
Pod B: Wake, NC State, VT, Clemson
Pod C: FSU, BC, L'ville, 1 more
Pod D: Miami, Syracuse, Pitt, 1 more

If the ACC went to 4 divisions, then it could do either 3-2-3 (8 games) or 3-3-3 (9 games) [division-protected cross-division-rotating]. I prefer 9 games because you can play everyone home and away at least 1 time in 4 years. I believe the 3-2-3 will take 6-8 years to do it. The 4 division format could look like this:

Division A: Duke, Pitt, Miami, Syracuse
Division B: Wake, L'ville, FSU, BC
Division C: UNC, UVA, GT, Team A
Division D: NC State, VT, Clemson, Team B

Under the 9 game format the protected groupings would look like this:

Duke/Wake/UNC/NC State
Pitt/L'ville/UVA/VT
Miami/FSU/GT/Clemson
Syracuse/BC/Team A/Team B

There is some flexibility on division alignment and protected groupings depending on who ends up being #15 and #16. Also, there could be flexibility on how the 4 division champions are paired for the semi-final round. The 4 division zipper model with 9 games would be the easiest to give schools equal access to all the regions and still be able to preserve the most annual rivalries.