This scheme is never going to be top of the league in rush yardage or rush Y/A because they don't want to be. Obviously they'd like to not allow long TD runs, but from an EPA perspective you actually want to encourage both the other team to run against you at a higher than average frequency AND be able to stop them at an above league average net YPA. If you're then also a top defense against the pass, as we are because we actually have good players and coaches, and play complementary offensive football (which we have struggled with as of late, but that doesn't mean the defensive philosophy isn't sound) you have a good modern NFL defense.