Top thing for me is that I've long suspected KY doesn't understand the college game very well. His offenses are static and his team doesn't commit to rebounding (which was masked by playing very, very bad early opposition with few tall players). BYU doesn't have Durrant and Booker, and the offensive sets that work for those guys will not work for Demin and Fouss. The effort necessary to win games in the Big XII has been notably lacking (except for Richie, who only knows how to play full out), and the look on KY's face as his team gets butchered tells me he doesn't understand why it's happening.
That's not to say Young isn't going to be a good coach. He's praised by players and coaches alike for his intelligence and his work ethic. Eventually that's going to produce good results, I have no doubt of it. But getting there will be a chore, and we're going to get to watch him do those chores in a very public setting. We're going to lose, I fear, and lose a lot, while Young figures out the sorts of things that make great college coaches. I hope--and I really do believe--that he will figure it out. Probably I shouldn't complain about it while it sucks in the meantime.
One caveat: it's possible that players like Dybantsa are just so good that it doesn't matter what kind of system you run, he's still going to go for 22 and 10 and eat the other team for breakfast. Totally possible. But this year's experience with two top draft picks is not encouraging on that score, and heaven help us if we have a year when we don't get guys who are just so tall that they can't help doing some things right.