82games.com just released their first detailed stats of the year, which includes one of my favorite stats, eFG% on jump shots.
To answer the question raised in the thread title, no, Rondo's shooting has not improved, at least in terms of efficiency:
2008-09: 43% of Rondo's shots were jumpers; .375eFG%
2009-10: 50% of Rondo's shots are jumpers; .379eFG%
In other words, his efficiency on jumpers through 8 games is virtually identical to last season. Other interesting stats? Rondo is finishing an amazing 75.9% of his inside shots this year, meaning he's getting a lot of open layups. Only 18% of his jump shots has been assisted, suggesting that he's taking a lot of pull-up shots (rather than set shots).
We, of course, know the issues with Rondo's early free throw shooting (he's shooting poorly, and is barely getting to the line at all). Similarly, he hasn't been attempting three pointers this year.
I'm not sure what to make of the numbers, other than I hope they get better. Rondo has been great passing the ball, and for the most part very good on defense, but shooting remains a large weakness.