Booker needs to spend some time in the weight room, he gets muscled off the ball quite often. But other than that and learning a few of the NBA tricks he seems remarkably ready to play in this league. And with him and Warren on the court at the same time at least we'll have some off-the-ball movement.
Seems like he forgets how quick the game is sometimes. He just made rookie mistakes by not protecting the ball and being aware of who's around. He took a bump from Lebron and still put it up with a nice touch. The strength will come as his body grows/ages. He still needs to fill out.