I'd love Rondo to have that mid-range jumper down. I'd also love for him to improve his free throw %.
Rondo's mid-range shooting percentage was top 12 in the league last year. For him to be a more efficient, he needs to shore things up with the short shots and the threeball.
With the space he gets from defenders for his mid-range shots, he should be top 5. If the other elite PGs received the shots he gets consistently, they'd be top 3 if not #1.
And yet some of the other elite point guards (start with Deron/Rose/Westbrook/Parker) are regularly under 40% on their mid-range shots. If the hit their open shots as well as you say (and, let's face it, everyone gets a decent amount of open jumpers, even players like PP and Ray and KD) then they must shoot very poorly on the contested jumpers that they take. What are we calling that? Ridiculously poor shot selection?
I know we've gone over this before, so I won't go BR the numbers, but I remember finding that Rondo's midrange jumpshot was assisted on a much higher percentage than other elite point guards last year, so he's not creating a midrange shot off the dribble in the same way a Rose, a Chris Paul, or a Tony Parker would.
Which isn't a good or a bad thing, but I think that posters are keying in on Rondo's ability (or lack-thereof) to get his shot off against an opponent in a 1-on-1 situation. A nuance that isn't covered exactly by just looking at his FG%.
Of course, if memory serves, you never really addressed that point the last time I brought it up, so I won't hold my breath for an answer this time. 
Not sure how I missed this one before. First of all, while it's clearly useful to compare the percentages, you need to have some idea of the actual numbers involved. In an average season Rondo probably has about 2/3 of his mid-range shots unassisted. If Rondo and another elite pg both took 10 mid-range shots, 6-7 of Rondo's would be unassisted and 8-9 of the other pg's shots would be unassisted. Not a huge difference. In fact it averages out to 2 or so more unassisted shots a week for the other pg.
If Rondo's making almost one-half of his mid-range jumpers assisted, on designed plays to get him open at the elbow, where he shoots a good percentage, then don't you have to treat those shots differently than a player like Steph Curry taking his player off the dribble or Chris Paul shooting a midrange jumper out of the pick and roll?
Secondly, you're claiming without any evidence that the difference in number of unassisted shots must be due to Rondo and other pgs trying to create those shots when it's just as likely (if not more likely) that they simply dribble up the court and take the shot if it's available whereas Rondo has the patience (and sense) to look for a better shot on a given possession. I don't think that not rushing to take low percentage shots is the problem you think it is.
The bold is another unsubstantiated claim, but that's ok, because I don't have the game tape handy to prove one way or the other.
Lastly, consider what you're saying. Every conversation revolving around Rondo and his jump shot involves many comments about how Rondo isn't closely guarded by defenders and how he's taking wide open shots (and passing up other wide open shots). Now you're coming along and claiming that Rondo doesn't have more unassisted shots because he's simultaneously open and unable to get his shot off against his opponent. It's hard to characterize that claim as anything other than absurd.
You're oversimplifying my second statement. Rondo doesn't, in your words, "rush to take inefficient shots." Ok, but I've never seen him be able to get his shot off against his opponent from the midrange or deep--it doesn't seem to be a part of his game. He doesn't take shots off the dribble--he drives to the hoop.
So, when we're talking about Rondo's mid-range efficiency and how it relates to other point guards, the fact that he doesn't pull up for midrange jumpers OTD very often, and instead gets most of his midrange looks on designed plays that give him space and time to shoot, means that he's taking easier shots.
That's not a bad thing,[in fact that's a good thing] but it does add a wrinkle to the idea that he's a better than average midrange shooter for the point guard position. If he's taking easier shots, shouldn't that inflate his FG%? And shouldn't that mean that we have to talk about Rondo's mid-range shooting a little differently than we talk about other elite PG's midrange shooting?
An final aside: I'm not sure why you're going with impossible to quantify conventional wisdom ["let's face it, everyone gets a decent amount of open jumpers, even players like PP and Ray and KD", "it's just as likely (if not more likely) that they simply dribble up the court and take the shot if it's available,"] to prove your point when you're so eager to use numbers most of the time.
Stats coming up in a second--the NBA stats website is kind of a PITA.