If you listen to SIRIUSXM College Sports Radio (ESPNU Radio) they harp on poor tackling when talking about a lot of teams in most conferences.
In the Big 12, I would imagine it is accentuated by the fact that offenses are intended to get offensive players in open space when makes it harder for defenses to defend one on one.
It's not great and unlike the nig 10 where its straight ahead just run into someone players actually are elusive and fast. But alot of good tackling is willingness, and at the college level isnt always there