not really sure why you wouldn't be impressed. it was well known before the draft and last year that he is a pass rush specialist and that what they really want from him.
he's a John Abraham type of rusher. he's not going to be stout against the run, he's not going to be a coverage LB, he's going to come off the edge and get to the QB.
Von and Watt are definitely more complete players but 19.5 sacks is 19.5 sacks regardless of if you can play the run well or not.