Ultimately I do think expansion makes sense for the conference. But you need the right teams.
I still think there are a couple ways to look at what the "right teams" are, and I'm not sure either of them sound as good when you actually list them.
There was an article a while back where someone did the math of what it would take to make the Big 12 Network plan make sense financially, allow it to improve the income for all the conference schools, AND to make Texas happy by giving them a big enough piece of the pie to make up for getting rid of the LHN. It basically said they would need to go to 14 schools (at least) and focus on state populations more than quality. As a result, BYU was kind of listed as a "maybe" while Cincy, Memphis, and one or both of USF/UCF were "must haves". UConn may have been "in play" there somewhere too.
It might work for the conference network thing, but I'm not sure it helps the conference to overcome any perception issues it has. On the flip side, BYU and Houston might be best if you're trying to fix (or at least do the least harm to) perception, but it hurts more than helps financially... a lot. Like, to the extent that teams SHOULD try to leave if they can.
If anyone can come up with a way that one of these dream scenarios could happen... Arizona and Arizona State (and maybe CU and Utah along with them)... or Arkansas and [someone?]... or FSU and Clemson (and whoever else could be mined from the ACC with them)... then yeah, the Big 12 needs to do it yesterday! But none of those things are anywhere close to likely right now, and to me, as a TEXAS fan (as opposed to a Big 12 fan), I feel like the best plan is to wait out the 10 team conference and get the escape plan to the Pac or B1G all set for if/when it's clear it isn't working.
But yeah, the ego stuff helps make sense of what all might be going on with Boren a bit more...