We have talent, and I think we'd pretty good if we had a half decent center. Even a Perkins or Joel Anthony (yes..ugh) level center would be a tremendous help to us if we wanted to win games. I've never seen a team that lacked as much size and interior defense as I do with this upcoming 13-14 Celtics roster (trades withstanding of course..).
We are relying on Sully/Olynyk/Melo/Faverani/Bass/Humphries/Wilcox (?) to defend the paint and stop penetration. I don't think any one of those players even specializes in being a tough defender. It's tough seeing us winning a ton of games when it's so easy to see where our defense will absolutely collapse onto itself. Not sure how we can win any more than 33-35 games without some proper interior defense. Like I said if we had a guy like Perkins, I'd actually notch us at around 41+ wins..not to say Perkins himself is even worth 10 wins, but he would stabilize our defense in ways none of our current players can.
Our defense around the perimeter is actually pretty awesome, though, between Rondo, Bradley, Green, Wallace, and Pressey's apparent ability to steal the ball.