I was thinking about this, isn't possible Rondo's lack of shooting creates a bias for him to hold the rock and create a basket directly, rather than facilitating general ball movement and good offense? Not necessarily a one person thing either - could be a subtle bias in everyone's mind (Doc, Rondo, the other players who don't move as much, etc.)
Just a theory... but fixable: Rondo can be a potent threat on back cuts and setting screens when he doesn't have the ball.