It seems like there's a lot of buzz right now about our need for another "3-down linebacker" that can solve our run D problems. The general feeling I get around here is that:
1. Pettine is a genius
2. We have a kick-ass DL that's generating a ton of pass rush
3. Our LB's are the weak link, despite the Legend of Kiko, because they're not stopping the run
I still maintain that Pettine is overrated (note that I'm not saying he's bad; I actually think he's quite good), but he's overrated in the sense that people are walking around like the Bills are a top-10 defense that's just a linebacker or two away from being dominant.
I think a lot of the pass rushing we've gotten this year came at the expense of run defense. Our DL's are also overrated in that they're putting up big sack numbers because they're becoming more one-directional. When your two DT's are nearing double digit sacks each, you're either super-dominant, or somebody's forgetting to block lanes.
Personally I think it's wishful thinking that another 3-down linebacker will solve our run D problems, unless we tweak how we use our DL's and how aggressively we pursue the QB's.