The thing is, I can give Capers some benefit of the doubt. Injuries to guys like Clay Matthews and Casey Heyward that definitely didn't make things easier (and injuries seem to be a recurring issue, maybe we should get rid of our strength & conditioning staff?). I can also be a bit forgiving as we have lost some key players and leadership in recent years in Charles Woodson, Nick Collins, Desmond Bishop, Cullen Jenkings, Nick Barnett, etc etc. Our defense is also quite young, as we've added a lot of young guys like Nick Perry, Casey Heyward, Jerel Worthy, Datone Jones, etc who have been asked to step in and contribute immediately.
So all in all I'm okay with having some growing pains over these last two seasons, but I would have liked to have seen some growth and progress from our defense, or at least from some of our young defensive players. And frankly I haven't seen that at all. And whether that was due to poor scouting/drafting by TT acquiring players who aren't good enough, or whether its just bad luck, the fact is the defense hasn't improved. If anything its gotten progressively worse. It may not be all Caper's fault, but the defense statistically (at least in terms of Total Defense rankings) has been on a consistent downward trend each year since he's taken over (with 2011 being the outlier as it was exceptionally bad) and i don't really see much reason to think it'll turn around.
At the end of the day, I wouldn't completely be against giving Capers one more year, but I wouldn't be against letting him go and going back to the drawing board defensively. Sometimes all it takes is some new blood and enthusiasm to get things jump-started. I mean look what happened when we installed Capers back in 2009, we went from being a bottom 7 defense to a top 5 defense 2 years in a row