Not arguing your stats but i think the reason alot of posters call him a pass rush specialist because when he was drafted most of his highlights was him getting to the qb and that kind of stuck.
But i think your post is on point. His biggest problem was and wouldve been was opportunity. I always felt DA ran this Big Nickel Base defense where the Nickel was like the 3rd LB, CG Johnson and Alontae Taylor were both very physical and had decent coverage skills so it always feels the SAM LB never gets a chance to shine in his defense