No negative plays. For some offenses, that's an emphasis almost as much as working to get the big play. But some offenses are better than others at this. To get a better gauge, I took a look at each Big 12 team's tackles for loss allowed per game. You can see the results below.
Tackles For Loss Allowed Per Game (National Rank to the left)
T-3) Texas — 4.08
T-13) Baylor — 4.46
T-16) Kansas State — 4.54
T-22) Oklahoma State — 4.62
26) Oklahoma — 4.73
T-36) Iowa State — 5.00
T-41) Texas Tech — 5.08
T-51) TCU — 5.31
T-83) Kansas — 6.00
114) West Virginia — 7.54
First things first, you can see that there isn't a huge gap between being tops in the league and being a mediocre team in terms of tackles for loss allowed. Had Texas allowed just one more tackle for loss per game, the Longhorns would have been tied with Texas Tech for sixth place in the league.
So why is Texas first? Consider that the Longhorns: 1) had a pretty experienced line going into last year, but 2) didn't play at a fast tempo, meaning they didn't get as many plays, and therefore as many chances for a negative play and 3) ran an offense predicated first on establishing the run, but rarely taking any huge risks. In fact, many of the league's top rushing teams are among the top teams in preventing negative plays.
With that in mind, Kansas is kind of a bizarro Texas. The Jayhawks were run-heavy and risk averse, but because they had no passing game, they took a really high percentage of sacks. And also because teams knew that they couldn't throw the ball, squads were able to load up the box and create negative run plays as well. So Kansas is Texas if Texas weren't able to throw the ball and had a worse offensive line.
West Virginia struggled to run the ball for much of the year, so it shouldn't be a huge surprise that the Mountaineers were far-and-away the worst at allowing tackles for loss.