The Big 12 really has two main priorities as it relates to potential expansion:

#1-Programs with elite brands that boost the Big 12 football reputation, and grow the per team media & CFP revenue.
#2-Quality programs with significant fan support that provide the Big 12 enhanced long term viability & financial stability.

In my view there are five programs currently outside the B1G & SEC that would fall into Category #1:
-Notre Dame, Florida State, North Carolina, Clemson, Miami
There are another five programs that fall into category #2:
-Virginia Tech, NC State, Louisville, Pitt, Georgia Tech
Then there are a few programs that don't quite fit the Big 12's needs but could be adequate additions if needed:
-Duke, Virginia, Syracuse, Stanford

Up until this week the assumption has been that at least 4 of the 5 programs in Category #1 were off the table as potential Big 12 additions. If ACC schools became available the assumption has been that the Big 12 would likely add four schools from Category #2 and sit tight. But if for some reason the B1G & SEC decide to simply not expand at all, or if they prioritize a few non Category #1/#2 programs, it may be in the Big 12's best interest to grow beyond 20 members.

The scenario that make things interesting is if the B1G decides to only pursue the combination of Notre Dame & Stanford to get to 20 members, which would leave North Carolina & Virginia available for the SEC to finally complete its southern footprint. Both conferences say they aren't interested in Clemson or FSU right now (though we'll see what happens if the ACC flood gates actually open). But clearly the Big 12 would have to invite Clemson, Florida State & Miami if they're on the table. And with all five of the Category #2 schools still available, it would make sense for the B12 to expand to 24 members if this is the case. Especially when we all understand that Clemson & FSU's stay in the Big 12 could be short lived.

The question is what should the Big 12 do in the scenario that there aren't a clear eight schools that provide the value they need?
Would they leave strong candidates on the outside that could provide long term stability if there are more defections?
How deep into that third category of schools should the conference be willing to go before they are simply adding schools with too little fan support & diluting the football brand too much for a conference that really can't afford it?