Unless Hightower has the ability to really get to the QB at his size, he'd be a luxury pick who is probably not worth taking at that pick (i.e. other players worth taking). Naturally, the guy would be a thumper in the run game. But so many teams go spread. What's his role in that situation?
If he becomes the dominant middle run stuffer as his size would suggest, why would teams even try to run it, in this era where everything favors passing? They'd spread the field, and either: a) walk him off the field, or b) make him cover.