I think he’ll get better once Delonte returns and becomes the primary ball handler off the bench.
I actually think that will hurt Nate's game. He is not a spot up shooter*. He plays much better with the ball in his hands, pulling up off the dribble. Conversely, Delonte IS a good spot-up shooter, and is a little out of control with the ball. So personally I hope it doesn't happen like you're suggesting.
It looks to me like Nate and Rondo don't mesh too well on the court together. Nate can't seem to find his niche as a 2 guard (again, because he's a poor spot up shooter*). I think Doc needs to change up the personnel he puts out there with Nate in order for him to be more effective.
*According to hoopdata.com, Nate was only assisted on 35% of his jumpers out to 23 feet, and 58% of his 3s. For comparison, Ray Allen was assisted for 79% of his jumpers and 92% of his 3s. Delonte was assisted on 80% of his 3s last year in Cleveland. Hence, Nate is poor a spot up shooter and scores best by creating his own shots.
link:
http://www.hoopdata.com/player.aspx?name=Nate Robinson