No - I'm not too worried. I think we're doing ok on D, despite the lack of sacks. What we really need is to give the D more rest, so that maybe they can be more effective. For that reason, I'd like to see more offensive production.
I think JPW is a good QB, though I wish he had a better long ball and could hit the WRs in stride. No real answer to that though, except more S&C training, reps, etc. But with our depth at RB, I think we could make some adjustments in the backfield.
I'd like to see more play out of Coffee and Upchuch. I know - Grant is the big threat guy, but because of their size, Coffee and Upchurch seem to be more consistent in getting those 3 and 4 yrds that sustain drives and keep our D off the field. Why no mention of Johns? I personally don't like his running style - too upright, high center of gravity. I think he is a great athelete though and should probably be used in some capacity (LB?).
I'd also like to see more two-back sets with Coffee or Upchurch and Grant in the backfield. An additional blocker might get Grant out in space more often, where he can really be effective. Maybe a few out-passes to Grant, again to get him the ball in space.
Bottom line: I think a few adjustments on offense would probably greatly enhance the effectiveness of our defense, sacks included.