I don't want to get ahead of ourselves here but adding Williams makes this defense potentially frightening. There's a lot of questions, Kyle's foot, McGee's knee, Merriman's body etc. But if, and that's a HUGE if Merriman could come back to form and Kyle returns at full strength you could be looking at a front line of Kelsay/Dareus/Williams/Williams with an LB group of Merriman/Sheppard/Barnett. That creates a MASSIVE problem for your OL because you'd have to double team 3 of the 4 guys. If you apply this to say a matchup against NE that means that Gronk isn't out in every pattern because he'd have to stay in just to keep Brady alive.
If, and again that's a HUGE if, this defense were to play out the Bills would be sitting sweet on defense. Draft a WR and CB and we could be down right nasty.