I don't think Hughton turned Becchio into a bad player, it was more the case that when he joined, the team were struggling to create opportunities for out strikers thanks to Hughton's style of play, and Becchio had a relatively small number of chances to get into the team, when he didn't do anything special. Also I really think Hughton doesn't understand the striker's part of the game, evidenced by him spending a fortune on RVW and Hooper, who just didn't fit in with the style of play that Hughton was using. And my guess is that Hughton couldn't really help strikers in training who were struggling on the pitch.
With hindsight it would have been worth giving Becchio a decent run in the team last January, but at the time the margins were so slim that Hughton probably didn't feel he could take any sort of gamble, also having spent so much on RVW I wonder if he felt he had to persevere with him ?