So let's say hypothetically, this were to happen. Would this be good or bad for ISU? The Big12 isn't going to collapse from this and it wouldn't be too hard to find another Southern school (TCU, Arkansas) that is willing to join. The conference may take a step back for a few years, but in the end I think this makes the conference as a whole stronger.
Also, I guess my biggest worry about all of this is that the Big10 decides to take both Missouri and Nebraska which very well could blow up the Big12. I think that the Southern teams would consider adding a few teams to restart a Southwestern type conference. That would leave ISU, Colorado, KU, and KSU in a bind and I think that the other three teams would have an easier road to find another conference. This is of course a worst case scenario for ISU, but I don't think it would be far fetched if NU and MU do indeed leave. By taking Texas, this would probably be off the table.