it's very difficult to put together two great units in such a short time period. For as young and ill-equipped, skill-set wise, as the offense was, he's put together a damn good one w/o the special effects of a speed back, like Hart and Hayes. The proble was two-fold, however, because on the high side he inherited 24 defensive players, barely enough for a two deep. By some counts, he only inherited 21 with a DL, great blitzing backer and cb on the way out.
You do the math and you'll probably come to a different conclusion and understand he had to spend a lot of time and recruits in repleneshing our offense, but all signs indicate the past two seasons, he's done the same with the defense.