He seemed to be taking more outside shots last year and hitting them at a decent clip.
I don't remember Rondo ever hitting outside shots at a decent clip. As the season wore on, teams sagged off him farther and farther taking away opportunities for assists. His assists went down due to this adjustment by other teams and Rondo was unable to make them pay.
Also back to my comparison to Ben Wallace. I wasn't trying to suggest that they were equal in terms of shooting but rather pointing out that a 45% shooting percentage does not prove Wallace is a good shooter any more than Rondo's 40% shows he is an average shooter.
I have been watching basketball for quite a few years (playing it too incidently) and I have never seen a guard get sagged off of like teams sag off Rondo. The only comparable is someone like Ben Wallace who teams don't cover outside of 10', just like Rondo.
That is the point. You don't need to look at any stats, just look at how teams cover Rondo. All the other coaches and players know that Rondo can't hurt them by shooting. The defense they deploy is essentially an insult to Rondo. The way to know when Rondo improves his shooting is by watching the defense on him, not by cherry picking stats.
OK, I know you're not comparing Rondo to Ben Wallace as an outside shooter, but I want to point out some flaws in your "comparison", nonetheless.
Rondo's not a 40% shooter. He's a 40% shooter from 16-23 feet. He is shooting .486 from the field for his career. His .475 from the field last season is his lowest since his rookie year. Ben Wallace shoots .475 from the field for his career, despite almost never taking shots from more than 10 feet out.
Ben Wallace is one of the worst shooters in the history of basketball, whereas Rajon Rondo is a mediocre to poor outside shooter.
I understand that this is apples to oranges seeing as Ben Wallace is known almost exclusively as a defensive and rebounding center while Rondo is a point guard.
Guys like Tony Parker, Russell Westbrook, Brandon Jennings, and Derrick Rose are all mediocre outside shooters, as well. They all get backed off and given jump shots, as opposed to being played up tight with the danger of being driven by, quite frequently as well.
One major difference is that most of those guys (with the possible exception of Parker) are not adverse at all to jacking up almost any shot that presents itself. Therefore, of course, they are played as primarily scorers much more than Rondo who is more likely to kill you with the passing game.
However, they are not significantly better outside shooters. If Rondo decided to starting being a gunner (or was forced to be), I'm sure he could score at the rate of those other point guards. I'm hoping he doesn't ever turn into a Russell Westbrook or Derrick Rose type shoot first guard, though.