I think people dramatically underestimate how good a player Roy Williams is. He is on a team that has no quarterback, and no running game, and yet he puts up fantastic numbers.
He was averaging over 5 catches per game, and was on pace for over 85 catches and 1,100 yards receiving. 2 years ago he had over 1,300 yards receiving and has 28 touchdowns in only 4 years. He's explosive, big, great hands, and YOUNG.
Saying he hasn't played well, or isn't worth a 1st rounder is just silly.
To address the 2nd portion of your comment, if we made the trade, I'm certain it would be contingent on negotiation an extension on his contract and locking him up for another 5-6 years.