I think a lot of it is his hustle and heart, which didn't seem to be there as much during the regular season. I credit that partly to the injury and reduced minutes after last year's stellar playoff performance.
That said, I think we do need to moderate praise and realize that part of his success is playing with Rondo, 3 Hall of Famers, and other strong players. He probably isn't getting open 18 footers and easy layups on other teams.
Still, the fact that he takes advantage of these opportunities should be praised. There's a lot of NBA players who wouldn't.