Our linebacker core definitely needs an upgrade, but I think what we saw in 2007 and 2011 were a result of our defensive lines more than great LB play. Remember in 2011, we almost didn't make the playoffs, playing terrible defense for much of the year as both Osi and Tuck spent time injured. We began to click as a defensive unit upon their return (and the timely returns of our secondary also). In other words, I think our, and generally speaking, LB play is a direct reflection of our defensive line's play.
I do agree with Titwio that our linebackers are going to become more important playing against Griffin twice a year. I know the pistol is the new rage, but I wouldn't put too much stock into it if Griffin weren't in our division or if other top teams in our conference didn't run it. We won't see San Fran every year, so I wouldn't cater my defense to it. I'm very interested to see what Chip Kelly does in Philly however, because I'm not sure he'll have the pieces for his offense OR defense this next year.