The more I think about it, the more it seems like it might be the right move for him. I mean if he puts up the same/similar numbers next year and is one year older, its doubtful he goes much higher than he would now. He could certainly benefit from a weaker draft, but its equally as risky as leaving now I think.
On the other hand, he could also come back stronger, refine his 3pt game and commit himself to getting rebounds (which he never really seemed to do) and really improve his stock.
He has NBA athleticism for sure, here's hoping that translates into a nice career for him.