The offense "can't sustain drives" because the defense can't make a stop and they're constantly playing catch-up. They don't have a problem sustaining drives in the first half for the most part with the exception of drive killing penalties, which I would guess are down from last year too, so there's another possible area of improvement. Playing catch-up is harder on the offense, not easier. So how does the defense making their job harder improve their point totals, exactly?
edit: team penalties 6.7 per game in '09, 4.6 per game this year, making us the 5th least penalized team. I didn't find stats for offensive penalties only, but if the team as a whole is averaging two less per game, the offense is probably averaging one less per game.