If BYU and Houston are the two adds, I would hate to see ISU, KU and KSU in different divisions. I think it is critical to keep geographic rivals. I would go with the following split:
North Division
Texas
OU
OSU
KU
KSU
ISU
South Division
TCU
Baylor
Houston
Texas Tech
West Virginia
BYU
Texas is the only Texas school in its dvision, but with 4 games against the other division, the will have 2 or 3 games against Texas schools each year.
I don't think that will happen. However, I could see Texas and WVU being flipped where BYU joins the 5 Texas teams and WVU joins the 5 Big 8 teams.
You would still need crossover to keep UT-OU rivalry.
Others don't really matter, but here are possibilities:
ISU - BYU
KU - Tech
KSU - Baylor
OSU - TCU
WVU - Houston
So if you have 1 guaranteed crossover, you would have 5 division, 1 crossover and 3 rotating out of other 5. I assume there would be a 2-year cycle of playing the same team.
So for ISU, play the following:
2017-18: Texas, Tech, Houston
2019-20: TCU, Baylor, Texas
2021-22: Tech, Houston, TCU
2023-24: Baylor, Texas, Tech
2025-26: Houston, TCU, Baylor
So we would play each of the 5 teams 6 times in 10 years. After the 10 year period, we would switch our crossover opponent based on order of finish during the last x years.