Yes, much love goes out to the 2 best players on the defense, no doubt.
The problem has been the inconsistency of the other players, besides Arrington.
Lesser named players like Ninkovich, Love, Deaderick, Anderson etc have been holding their own, and even looking pretty good at times. I would even add Ihedigbo to that list, as he has not played "good," but he has proven to be a worthy enough player under the poor circumstances.
There are going to be mixed feelings on Mayo, but he has proven himself to be one of the core players..no doubt. I think we may need to see a bigger role from him overall, and that may come. If so, it would be huge. He is certainly a very talented player, but still hasn't taken that final step that so many of us expect.
The main problem has been due to injuries and inconsistent play of guys like McCourty, Chung, Spikes etc. Those are the players that so many of us thought would make this defense a competitive unit. Whether it's poor play, bad luck with injuries, or a mixture of both (all 3 are candidates), they ALL need to contribute for this defense to be anywhere effective.
Hopefully having Fletcher back will make a very positive impact. Even a lesser role playing Guyton could add something when healthy, if used in spot/role playing duty and not as a starter. The unit has a lot of potential, but has not lived up to it for one reason or another; obviously including injuries.