People thought TCU wouldn't be meaningful, but they are. Of course, the only sports that really matter are basketball and football.
Bring in South Florida and Houston and call it day.
Houston football could turn into something good, and they would bring basketball into the conference with Kelvin Sampson roaming the sidelines. Great recruiting area for them as well.
South Florida currently plays in the American Athletic Conference, and this would be a big upgrade for them. They have a 50,000 student enrollment, great recruiting area, ranks in the top 100 public universities according to US News college rankings, and they have a great stadium as they play at Raymond James Stadium (same as the Tampa Bay Bucs). Their basketball arena is the Sun Dome which holds nearly 11,000 and they just completed a $36 million renovation to it.