Here is what UW's D-coordinator, Kill's replacement at NIU, said about TCU's offense:
"I think they're balanced," UW defensive coordinator Dave Doeren said. "They're good at taking what you give. They mix it up a lot (with formations). They don't have a ton of plays, but they have a lot of formations and ways to get to them. They do a really nice job."
I see Kill as trying to be similar to this. You don't always need a hundred different plays, just different ways to beat a defense with a basic group of plays. Interestingly, when Kill went to NIU from SIU, he and his staff spent some time at Boise State with their coaching staff, just exchanging ideas re: offense and defense. Additionally, when Kill went from Division II to SIU in 2000, he went to K-State and spent a couple of days with Bill Snyder to pick his brain about reviving the Division I-AA equivalent of 1988 K-State, or as close as possible to it, that SIU represented when Kill went there in 2000. Snyder apparently liked him and was willing to spend some time with him.