To me it's not so much about the Big 4 it's that we have an opportunity to put the 6 original ACC schools together plus GT (the next oldest member) in one division and the 7 newer schools in another division which keeps a lot of traditional rivalries in place (not just big 4 but also Clemson-GT, FSU-Miami, Pitt-Syracuse) while also having pretty good competitive balance:
Atlantic:
Clemson
Duke
Georgia Tech
North Carolina
North Carolina State
Virginia
Wake Forest
Coastal:
Boston College
Florida State
Louisville
Miami
Pittsburgh
Syracuse
Virginia Tech
The only real drawback I see is the travel for the Florida schools. I think it would really keep up (and maybe spike fan interest)....
Best Proposal I've seen