In what universe is he not pretty much already there? Passing, rebounding, and defense are all easily comparable. Equally streaky shooters. Kidd might have had a slight advantage at posting up and getting to the line, but overall Rondo is a much more efficient scorer.
It's not like he needs this giant leap or anything.
Yeah, I'd say he's pretty close already. I think he is missing one thing.
Magic Johnson constantly talks about, as a point guard, feeding guys at the appropriate times for a variety of reasons (maybe to build their confidence, maybe to get them to work harder on defense, etc...) and also the skill in finding the right guy with the right pass - some guys are better at catching different passes and like the ball in different spots.
Rondo has some of this skill, but not to the level of Kidd. Look at how much money Kidd made for Kenyon Martin, Richard Jefferson, and even Mikki Moore due to his ability to feed them with the right pass in the right place at the right time. He made Mikki Moore look so good he got an $18 million contract with the Kings! Rondo would've never made Mikki look good enough to get $18 million.
It is hard to describe exactly, because it is so innate, immeasurable, and intangible, but I'd say Rondo is very close but is a bit lower on the "floor general", let's call it, scale than Kidd.