I've been thinking way too much about this.
I think that competing with the B1G in SoCal and the SEC in TX while encroaching on their territories is the move. So I'd expand beyond 16 while going with the strategic G5 partners that accomplished this or severely weakened media value from overlapping G5 conferences or gave additional in-footprint value or additional media opportunities due to having an audience that exceeded its in-footprint value. I would also want to maintain regional & rivalry strength to drive fan interest & reduce costs for all the non-revenue sports.
Here's a first stab at it
Pac-12 selections:
1. Washington
2. Oregon
3. Stanford
4. Cal
5. Arizona
6. Arizona State
7. Utah
8. Colorado
Locks down all footprint states while doubling down in the huge Bay Area media market and the AZ market which is growing like nowhere else but GA. I take UA, not just ASU, due to the name brand (even it's mostly in hoops) because this conference needs cache. WSU & OSU get left behind because they don't add markets or prestige.
Big 12 selections:
1. Baylor
2. Houston
3. TCU
4. Texas Tech
5. Oklahoma State
6. Kansas
7. BYU
8. Iowa State
I left off KSU because there's almost no value in having 2 teams in KS, the same logic used for leaving out WSU and OSU from the Pac-12. BYU gives international exposure, network and resources of the LDS church along with a very valuable rivalry matchup with Utah. ISU encroaches on B1G territory and I think keeping an AAU member makes some of the other choices more palatable to members like Stanford.
Sitting at 16, we now look at gaining more markets, setting up compelling matchups to draw eyeballs, and putting up a fight against B1G/SEC dominance.
G5 selections (would get reduced media shares):
1. San Diego State - consistently good football (with great basketball prestige), new stadium that makes them legit for playing on this level, and the #27 San Diego media market to make sure not to give away SoCal to the B1G.
2. Boise State - national reputation for football, new in-footprint market with one of the fastest growing states, and what has been the member driving a lot of the MWC tv value.
3. Fresno State - again a move to have a presence in SoCal, adding a nationally respected football program in the #55 by market which has a main rivalry with Boise State. One of the better tailgate & stadium scenes in the west. Fresno-Visalia market, while smaller, is still the size of Buffalo or Memphis, so it's significant on top of its SoCal value.
4. UNLV - Nevada is one of the fastest growing states (about the size of Utah), plays in a brand new NFL stadium, has a national brand for basketball, helps a bit to wall in and encroach on the B1G's LA circle of influence, and gives a rivalry matchup with SDSU.
The above is if we go to 20. If we want to take it to 24 (and we'd have to further reduce media shares at this point), I believe the 4 which make the most strategic sense are:
5. Air Force - international media reach, a football rivalry game for CU, an appropriate stadium that seats about 50k, and a good media draw. In-footprint, the Colorado Springs-Pueblo tv market is #82 (right in between Madison, WI and Waco, TX).
6. Tulane - encroach on SEC territory for recruiting and media (New Orleans is #50 for in-market TVs), and soften the blow to some of the academic-minded member voices by adding a top AAU member.
7. New Mexico - ABQ-Santa Fe TVs is the #48 in-footprint market (larger than Louisville, New Orleans or Memphis), and expands the map like with Boise State. Elite basketball facilities with a dog of a football program and a stadium that needs to be upgraded.
8. UTSA - home stadium is the 72k Alamodome, in-footprint TVs (#31 ranked market) is the same as SLC with a bit over 1M, and further dilutes the SEC domination of Texas.
Last, this leaves some expansion targets which make sense for the ACC to follow a similar blueprint (Cincinnati, West Virginia, Memphis, UCF). Scheduling alliance with them - especially for outside of football - would be good for both. And the better defined footprint regions makes things survivable for both if the SEC and B1G poach members in the future. Lose TCU? Add SMU. Lose KU? Add KSU. Or for the ACC, lose Miami add UCF and so on. So if we end up with a longer-term reshuffle to a Power 2 instead of a Power 4, there would still be a framework for there to be a very respectable G2.