Projecting DT / NT is a dangerous thing....if it were as easy as many people THINK it is, then NFL teams would have a much better success rate at drafting quality DT and NT in the early rounds of the draft. As it is, there is about a 50-50 shot that talent and ability at a previous level will carry over to the next level and I think this is even smaller on the HS-to-college transition than the college-to-NFL transition.
The only reason ND "needed" Omar was to play the percentages. If the incoming class had kept Newman, Hunter and Cwynar, then the chances of having at least one of them be a dominating college player were virtually certain. Losing Hunter from the class makes it more important for Newman and Cwynar to be as good as advertised and have it translate to the field in D1 ball.
All of that said, the emergence of Ian Williams in the second half of the season was more important than Omar Hunter's decision to drink the Urban Kool-Aid. Williams has SHOWN college ability on the field. Hunter (and any other recruit for that matter) have shown HIGH-SCHOOL ability. That's definitely not to say that Hunter is going to bust - hell, he may wind up as a collegiate hall of famer for all any of us know - but it is enough for me to brush off his defection and move on....