I'm not writing off Vargas but he does have to make some serious changes to his swing/approach. The PULL THE BALL IN THE AIR swing/approach simply doesn't work. His hands are too close to his body and he has a steep entry w/an extreme uphill path. There's just no room for error with that stupid swing/approach.
I hope they go back to basics with him because he does have bat speed and suddenness to go along with a great eye. I'd move his hands away from his body, shorten and flatten his swing and concentrate on barreling the baseball and hitting line drives. If he does that he has a chance to be a good hitter but if he continues with the PULL THE BALL IN THE AIR thing he's done.