I assume one thing, and then I really only have one major point to offer to the maelstrom of commentary that is already taking place.
Assumption: It is all about money (I also have no problem with that, if anyone wants to throw down a politico-economico-moral argument over the matter). Things like football tradition, cultural "fit", and so forth do play some role in this, but not in a "we have to pick a school that meets these criteria" kind of way. Rather, the school that is the best money fit will, almost by definition, be the best combination of those other criteria as well. The other stuff is already "included" in the price, as it were. When you take into account the headaches of travelling and getting along in all the other sports, cultural fit and geographical proximity and so forth pretty much become part of the money equation, and not some extra considerations that you have to worry about after you've figured out which option is the best economically.
So, What I'm Thinking
It's all wrong to ask "who is the 14th SEC team?" in a vaccuum, and then pick apart the various possible candidates in terms of this or that. The 14th team in, frankly, is going to be a very fortunate program that is getting in because the SEC basically needs somebody to come in along with Texas A & M.
It's all about the money, yes, but the money issue is "won" already by bringing in Texas A & M. At that point, you simply need to bring in a 14th, and almost any 14th will do. It doesn't even matter if the 14th team sets you back a bit in terms of money, because overall you are picking up gains by adding Texas A & M and that team.
In other words, the decision is not, given that we have 13 teams, who should the 14th be? Rather, the decision is, given that we have 12 teams, does expansion to 14 make sense? The answer to that question (apparently) is that, yes, it absolutely makes sense if Texas A & M is one of the two schools added. That is the necessary and sufficient condition for expansion to make sense. The particular identity of the 14th school is almost an afterthought. Which is why whoever finds their way in to that slot should give their AD a raise (or, in the case of WVU, perhaps just call this year a wash).
Think of it this way. Right now each of the 12 members of the SEC makes $X per year as a result of their conference membership. By adding Texas A&M, each of the 13 members are going to make some new amount $X + n. Something higher than the current X (and it's probably a home run, no-doubt-about-it kind of number that makes the decision a no-brainer). Now, at that point, sitting with 13 teams making $X + n per year, you need a 14th team for a variety of reasons. But it's entirely possible that there is no 14th team you can bring in that will move the money needle up any further. It may even knock it down a bit. Maybe no matter who the 14th team is, the per school share of money in the new 14-team conference is going to be something smaller than $X + n. But, that's completely, unequivocally, absolutely...OK. It does not matter if the 14th team down-ticks you just a bit, so long as you're still going up on the net compared to what you're making with only 12 teams. I think that's the situation the SEC is in here. Texas A&M as number 13 makes a lot more money for everyone. At that point, logistically we need a 14th. The 14th just needs to be someone that still lets the dust settle with a lot more money than the member schools currently make, even if that 14th school doesn't actually add (or even if it slightly detracts, theoretically) anything more to that number.
SEC schools will end up making more with A&M-plus-one than they currently make, so the whole move to go to 14 is a net gainer. That being the case, the 14th just needs to be a reasonable team. Not a homerun. Not a crown jewel. Not an excitement machine. Just a warm body that can hold its own and allows the conference to have 14 instead of 13. This is why the SEC is likely not in any hurry to go "recruit" anyone in particular. In the coming chaos, someone who works will come calling, and that will be fine.
So Who Will It Be?
Of course, the SEC isn't literally going to take just anyone. Frankly, I think you basically just have to ask and be a non-terrible program in a current AQ conference. That is a pretty modest criterion, but not everyone can meet it. I imagine it will be a team not already in an SEC footprint state, and probably not in the ACC (now that they're re-upping thier walkaway fee and showing some solidarity; I think an ACC school such as NC State or Virginia Tech would fit the bill if they asked, but I don't think any will ask. I could be wrong.).
Among the current most obvious subjects of banter, West Virginia and Mizzou would both do, although West Virginia is preferable because they would go into the east and not require any further re-shuffling of the divisions. If the rumors are true, West Virginia is about to ask, and there you go.
It doesn't matter if WVU does or does not bring in more eyeballs in the Pittsburgh market or anywhere else. It doesn't matter if the Mountaineers are a non-tight cultural fit, as long as they aren't absurd (and, honestly, they're about right). It doesn't even matter if WVU is a net money-loser in its own right. The issue is that, with A&M joining, the SEC is going to make more money per school than it does currently. A team like WVU coming in at that point is still going to maintain a net gain in per school money, even if WVU technically ticks it backwards a bit.