"He needs to learn to adjust at the plate you don't do that in the biggs."
The majors is exactly where you do that. He's already proven he can crush the ball in the minors. If you haven't seen his stats, look again.
Also, the idea he has a whole in his swing or can't hit lefties has been debunked by FanGraphs.
His problem is that he puts pressure on himself to perform quickly because he knows Bochy will bench him for Huff at the drop of a hat. If he knew he'd be playing on a consistent basis, he'd be a lot better than he has been.