see how the SEC's projected number (16) after UT and OU addition is based on 16 being an ideal number. I think its more just happenstance. I see how more is helpful if you have your own tv channel that needs to be supported with inventory, but I don't see a rebuilt big 12 conference is going to get their own tv channel regardless of whether they have 8 or 20 or something in-between schools.
The more teams that are brought in, the less often that the teams play half of the conference.
A conference ought to be a way to build a bunch of rivalries by actually playing the other teams every year.
Georgia and Texas A&M have played football against each other one time in A&M's ten season of being in the SEC.