1. Rondo doesn't try during most regular seasons games
He's less aggressive on the boards, less willing to attack the basket, etc. And I kind of agree with this point. I'd rather see a healthy Rondo in the playoffs than an injured Rondo watching from the sidelines.
2. Defenders still don't respect his jumper
Even when he's mailing it in, somebody like Ray Allen can help an offense because a defender needs to respect his shot. This isn't true for Rondo. Rondo is useless without the ball in his hands.