Here are our 2008 recruits in the defensive side still with the team (original class commits Marcus Witherspoon and Taylor Hill transfered, list generated from Scout):
Cissoko has struggled, to put it moderately. Smith is playing on most special teams and was moved to LB, Floyd had an opportunity after Cissoko, the coaches evaluated, then moved Woolfolk back to corner in his place. Demens and Fitzgerald are backups, and despite the struggles of Ezeh and Mouton have not been able to merit real playing time, with Kevin Leach, a walk on, logging more playing time. Martin is a man-beast that should have a great next couple of years.
So. These kids are sophomores/redshirt freshmen. Therefore they can and do have time to improve and contribute to the defense in later years. But I think it's fair to say that with the lack of top talent on the defensive side, that this class would ideally provide a critical layer of depth, and you would hope that some would be pushing upperclassmen for playing time. That has not happened yet apart from Martin obviously. Keep your fingers crossed that growth, Barwis, maturity and another year of age changes the fortunes of this class for the better, because we need them.