I, too, see the same thing you do on defense. Our run D is decent, our coverage is much better than last year, but our pass rush is hopeless. The best outside pass rusher we have is Matthews and he only comes to play a couple of times a game. Perry has shown next to nothing rushing, although he is a good run defender. Fackrell's number is never called. Brooks may have been the best edge rusher, but he's only played a couple of games after having very little injury history.
I'm not even seeing a push from the inside. Last year, Jones, Pepper, and Daniels got some inside rush and pushed the pocket a little allowing Perry and Matthews to pick up sacks. This year, Daniels, Clark, and Lowry get very little push although they play the run well.
I suspect that the lack of inside pressure is the biggest difference in our pass rush.