Despite the fact that he's got the "project" label, Boyle really has progressed well as a prospect; there haven't been any sizable blips in his development up to this point so I think it's premature to start labelling him as a bust. He's now at a critical point in that development: making the jump from college to pro hockey. I'm sure a year in Manchester will help us to get a better read on his potential; moreover, I think we should reserve any damning judgement at least until that year is complete, because, other than the fact that he was an off-the-board pick, he's done nothing to indicate that he's not going to pan out to at least some degree.
I will say that I'm wary of the decision to move him to defense (if such a decision has, indeed, been made); the guy was drafted and has developed up to this point as a forward. Switching his position at this point in his career just seems kind of risky. However, I'm sure management wouldn't do such a thing unless they had thoroughly assessed his game, spoken with him about it and were confident that he could handle playing D.