Some would say that Rondo, the smallest player in their rotation, has been the difference for the Celtics so far and Allen has had some great games in the playoffs.
Bigs seem a lot bigger when you have someone able to get them the ball in a position to do some damage.
To be honest, I don't see why MDA would be unhappy with having and coaching the Celtics lineup except for Rondo's lack of an outside game, and I expect that he would see Rondo's distribution skills and D as compensation. Wallace, Garnett, and even Davis have outside games, and of course, MDA would love having guys like Pierce and Allen on the perimeter.
You always want some kind of size balance, but, as someone pointed out, having some skills, whether you are big or small, is a necessity. And I don't think people should dismiss the significance of a player's "character," although character without skill means you have a good teammate on the bench and nothing more.
No man is happy without a delusion of some kind. Delusions are as necessary to our happiness as realities- C.N. Bovee