Rondo in a motion could work, but I think he does need to pound the ball less. Parker holding the ball is less damaging to the motion, it seems to me, because he runs around like a mad man, weaving through screens and quick hand-offs (that sometimes immediately return to him). So Parker is in motion, creating similar chaos to ball movement. Rondo's skill is in taking his time, slowly maneuvering the chess pieces into position, then making his big move, whether it's a drive-and-kick or what have you.
I wonder if Rondo would be more willing to pass and move off the ball if he had more stars, better shooters, and better passers. Also, it is worth considering that Parker is not the best jump shooter, and he is much, much improved. Rondo is also improving quite a bit, and he is very efficient with elbow jumpers in particular. His 3-point shot is better. He's not a deadly threat in this way, but he might not have to be.
With all this said, I think Stevens' system will develop into something quite beautiful, in the mold of the Spurs. This could happen with a Rondo-Love-Melo team, as Melo and Love are both good, smart passers (despite Melo's ridiculous reputation among some haters), and elite shooters. His system could also develop with a young core, if we don't land a big trade (but instead clean house and deal Rondo, etc).
Final thought. Here are some current C's who could play in a truly great motion offense: Rondo, Pressey, Sully, Olynyk, Green, and Humphries. I'd say Faverani, Johnson, and Iverson all have the capability to develop into great cogs in a motion-machine as well. AB's great coming off screens in a catch & shoot and cutting to the basket, but I don't see him as a great passer. In the draft, I see Parker, Vonleh, Gordon, Smart, Saric, McDermott, Stauskas, Harris, and Payton as great potential fits as well (and probably others too, but those are the dudes that come to mind).