Actually, it's one of the easier positions to evaluate.
Based on what?
What traits are you meaning besides what I've already said? He has the height/size, an alpha dog mentality and can make spectacular catches. What other above average traits does he have?
I'm less concerned with pure speed than I am with guys who consistently get OPEN and CATCH the ball. Harry is great at catching the ball...just not at getting open. Metcalf is better at getting open, but not nearly as good at catching the ball. Easier to refine catching skills with an explosive athlete. Can't teach a good athlete to become great very easily. But either way can be highly successful...but can also bust. Both are projections.
I haven't tracked his route tree in college, but he ran other routes too. What evidence do you have that he is explosive and sudden for his size? These are the two things most people are down on him about (and most likely why he won't run a 3 cone or 20 yd shuttle).
Well, Juju is what you HOPE Harry becomes...but Schuster also wasn't the #1 wr on his team. It's a lot easier when you have AB drawing a lot of coverage, an excellent OL and a Pro Bowl QB throwing the ball. And Pitt has a nice track record of developing wr's for quite a while now. But Schuster had a lot of the same issues coming out of college. He needed to learn to run better routes to get open. He did that...but that's also why he went in round 2. When you have to learn something that important, it doesn't make you a first round draft pick. Could Harry become that good? Yes. Can Marquise Brown be the next Desean Jackson? Yes. Can Metcalf become Calvin Johnson-lite? Yes. But that's their ceiling. Metcalf has the best ceiling, but also the lowest floor. I don't think we want a guy who we don't know if he'll be able to get open or not...at least not in round 1.