I think for Rondo, he is an unusual case when it come to shooting, He's a point guard with hands the size of a PF/C. So i think he needs to focus more on hand placement on the ball rather than form. hand-placement would be an aspect of form i suppose, rather than getting a total revamped shooting form. He needs to adjust his hands on different spots on the ball to find what works for him. he also needs to work on hand-placement on the ball, "off the dribble , into a shot" as well as hand placement on the ball "off of the pass into a shot" and passes from all different angles.
I just believe his hands are holding him back because their just, Quite Frankly, HUGE! He should focus on the small things like hand placement, b/c with his hands so big, he has little room for error when it comes to hand/finger spacing on the ball on his shot.