Heathcot by far has the best tools and highest ceiling of anyone in the system. He has very similar tools to Trout, not saying he will ever turn into that. If he stays healthy it wouldn't surprise me if he over took Williams as our best prospect.
As far as the rankings i'm a little surprised that BA had Depaula 10th, they have been raving about him for a while and another very credible prospect site who just released their top 50 Yankee prospect rankings had him 6th, the only pitcher he was behind was banuelos. Mark Newman also raved about him and his stuff , ceiling and work ethic in a recent interview. IMO stuff wise he's way ahead of Campos