Recruiting is difficult in the first place. Recruiting to a very religious school in the cold rocky mountains with a strict honor code and two year missions is just flat out difficult. No other coach in the nation at a major program faces the same types of challenges that Bronco does.
I think the biggest problem is how missions keep a team from reloading properly. In a normal program, a coach will know if a player is bust within a couple of years. To compensate, he'll immediately recruit extra players at that position to compensate and hopefully get the problem fixed rather quickly.
At BYU, you don't know if player will meet expectations for nearly 3-4 years. That's just crazy. In the meantime, you focused recruiting on other areas to find out that you have a big hole where you didn't expect it.