of his defense, his choice to stick with his defensive coordinator, and the lack of production on the field by the defense are all valid. As you pointed out, there are stats, analysts, and casual observations that all indicate that the defense is lacking. 21 - 4 is awesome but you also have to remember that one of those seasons was against a C-USA/Sun Belt level schedule. That helped a lot.
The truth is, BYU's defense plays not to lose. They don't play to win.