Why do people worry about "traditional rivalries" of the old Big 8? The only true rival was OU. That's it. Colorado and KSU had strong periods but neither was sustained... The Big 8 died 15 years ago, the Big 12 was never more than a glued up, pieced together piece of crap so why would we care that the glue finally gave and the crap has fallen apart...
Kansas a rival? No, it was a habit (100+ years, but irrelevant 90+ of those years...).
The Big 10 has forgotten more tradition/history than the Big 12 ever had...