I agree that DC's strict program has contributed to the high level of attrition since he arrived, but I think we would be amiss not to mention another contributor to the problem...he seems to favor the players he recruited over the players who were already in the program when he arrived.
One good example of that, which has already been brought up, is James Davis. I specifically remember DC justifying Alexander seeing more playing time over Darius Terry (captain) based upon the two RB's YPC average. Against SUU, Alexander averaged 3.1 yards per carry while Davis averaged 7.0 yards per carry. One would think that would warrant Davis at least getting the oppurtunity to see more touches, but instead, Davis saw only one carry in the Texas game and none in the BSU game.
Another example that caught my attention (and one that I brought up at the time it happened) is the seemingly opposite ways he has handled injuries and how those affect the players position on the depth chart. If you guys recall, Fred Givens was injured and missed nearly all of spring practice in 2009. At the conclusion of spring drills, Givens was listed as a back-up and most posters dismissed it assuming Givens would win the job back in the fall. However, the way DC handled the Kankolongo injury was totally different. If you recall, DC stated several times that he wouldn't move Kankolongo down the depth chart because of his injury.
I do want to clarify that I'm not trying to bash on DC. I still think he was a great hire and his strengths far outweigh his weaknesses. I'm simply trying to point out another possible contributor that I hadn't seen anybody mention yet. Fell free to agree or disagree.