Jefferson certainly has a chance to be a very good player. He has the athleticism, smarts, and work ethic to become an all-star.
RJ has an all-around type of game, he's willing to do whatever it takes to help the team win. R-Jeff is great on the break, a very good passer, good rebounder, great defender, and he has a very quick first step. From what I hear, Jefferson HAS added a 3-point shot to his offensive arsenal and has been working with Net trainers all summer.
Top 10 in the NBA? Absolutely not. Top 20? Most likely.
Here are my predictions for his numbers in 3 years.
20 PPG
7 RPG
5 APG
It's ridiculous RJ didn't make All-Rookie first team OR get invited to the Rookie-Soph game. IMO, he showed more than any rookie in the time he was given, including Gasol. In the 9 games he started because of K-Mart's suspensions, he put up, I believe, 16, 6, and 3.
(Also, that fade-away from the post you mentioned is a kickass move! He must have nailed that 10 times in the summer league games I watched of him.)