Most definitely injuries, coaching and level of talent all play a factor in it. I also acknowledge that it is hard to coach up a player that is getting injured all the time like Kevin King. Maybe had the Packers defense stayed more healthy during the season, we would have seen a bigger improvement than we did, I can't dispute that. But a few of the players that did stay healthy, didn't really show much improvement. So what continues to give me pause is with the amount of draft capital invested in the defense over the last 7 drafts, we should be a whole lot better than we have been. Even this upcoming draft looks like its going to again have to concentrate heavily on the defense. Sure, the failures of all that draft capital can be blamed on TT and bad evaluations, but I think when you mix in the fact that some of those players have left Green Bay and played better, coaching is still a big factor.
We can only hope Pettine is the guy and he along with LeFleur, are able to put together a solid bunch of assistants, because IMO, that is going to be the key to really improving our D.