VT is more tied to UVA than NC State is to Duke and UNC. In fact, if I remember correctly, UVA would actually have to vote to allow VT to leave the ACC.
It appears that the new status quo for conference stability seems to be none at all so I don't think you can say anything in absolutes but, I think the only scenarios where VT joins the SEC is if they came as a package deal with UVA (which UVA would never do). Or it was timed with a move from UVA to another conference (maybe follow UMD to B1G), although the ACC would fight tooth and nail to never let them out.
I didn't mean to get conf. expansion talk going but this has been interesting.
I agree with a lot said.
1. The SEC, if they ever add two more schools, will be two schools from two different states. Only way the pie pieces continue to get bigger even though you add two more slices.
2. UNFORTUNATLY for us NC and VA are the obvious choices for exansion which is why I hope they don't expand.
3. I agree that the next SEC expansion would be pre-planned but wouldn't happen till another expansion domino fell first. For Example. Big 10 comes down and grabs Virginia and GT. That sends the ACC into a tizzy and Clemson, Miami and FSU up and roll to the Big 12 along with BYU or Cincy or any other team. Then SEC plucks NC St and Virginia and UNC and Duke are like WTF?
Or the Pac 12 could nab Texas and some schools setting off a reaction that causes Oklahoma to break free of OK St.
4. A 16 team league would be really cool but would present challenges for TN if a school is in NC (even though I think NC St would take a long time to get up to speed like SC has). 16 teams each playing 9 conf. games a year. Each team has 3 rivals they play each year. Then the other 6 games rotate between the other 12 teams home and away every 4 years.
Bama - Tennessee, Aub, Miss St (2)
Ark - LSU, A&M, Missouri (1)
Aub - Bama, UGA, Ole Miss (2)
Florida - LSU, UGA, Missouri (2)
Georgia - Florida, Auburn, SC (2)
Kentucky - NC St, Miss St, Vandy (0)
LSU - Florida, A&M, ARK (1)
Missouri - Florida, Arkansas, A&M (1)
Miss St - Alabama, Ole Miss, Kentucky (1)
NC St - South Carolina, VT, Kentucky (0)
Ole Miss - Auburn, Vandy, Miss St (1)
South Carolina - UGA, NC St, VT (1)
Texas A&M - LSU, Arkansas, Missouri (1)
TN - Bama, VT, Vandy (1)
Vandy - Tennessee, Ole Miss, Kentucky (1)
VT - Tennessee, South Carolina, NC St (1)
The number in () is number of BIG 6 matchups per team. No way to get 2 on each BIG 6 team without giving one of the BIG 6 3 which would never be fair.
So to compromise TN and LSU keep the strongest of the new teams VT and A&M to build new rivalries.