Turner will always be a player that gives with one hand, and takes away with the other. He's not of starter quality because his game needs the ball in his hands at all times, but he doesn't have the skills to allow that.
He is not a great passer, not a great shooter, and he's reckless on his handle.
He's a good guy to have on the bench, because he can function at many positions. If he hasn't grown his game by now, it's not going to happen.