wingspan, I believe, is an underrated stat by most football fans. In the NFL, an inch matters. I"ve know of some very good college LBers who fell in the draft because of short wingspans. As they have to cover TEs and RBs getting a finger on the ball often means three and out or a first down.
Arnold's wingspan is pretty long. TCF is long for a CB, if he has the speed at almost 6-1 for the NFL. He could also put on 15 lbs and move to S over time.
Amazing that PSU had two of the best rookie defenders in all of the NFL. I think it is possible that we do that again next year in Arnold and Brisker.