Well, maybe he was a backup at OSU for a reason.
Why do you think that was?
It's a great question. Hall did play behind some noteable guys like Santonio Holmes, Ted Ginn and Anthony Gonzalez. Just look at where those three were drafted. Robiskie is a great talent, too.. As to why he didn't do more? I can't answer that. I'll throw some ideas out there though.
..maybe he was more willing to fill the special teams role and do the smaller things the coaches wanted. Hall was utilized around the goal line, 3rd downs and other key situations, so the coaching staff obviously had trust in him.
..maybe he's just not as talented as those other receivers. That might not be such a bad thing either. It could be a numbers thing. He has great size and speed. His hands, to my knowledge, don't appear to be in question. Otherwise, why would the Buckeyes use him so much in key situations?
I think Gonzalez is the better 1-2 year fantasy prospect, but after that, Hall is probably a better value and he could have just as much of a ceiling long-term.