Yes, he's got stuff to work on for sure. And the challenges will be different. If he rakes AND they need someone to play 3B AND he has the arm to play there he should be considered and not held back by some magical number of ABs he must have at each level.
The Cubs haven't seen a batter this polished in a while. Probably not since Mark Grace.
Also, I kind of believe the criticism is one based not on observation, but on expectation. He hasn't had to be patient because he's destroyed everything in his zone. Why take a walk when you can hit a double? But whatever, I agree. In theory, he will need to learn discipline. We don't know that he doesn't already. He walked more than he K'd his final year of college.