The biggest issue that I see with the Metcalf hype isn't his poor agility times- it's that he had such poor agility times versus such strong 40 and jump measurements.
The jumps and the 40 are important because they show how much raw athleticism is there.
The agility tests are important because they demonstrate how that athleticism is funneled into the whole player.
The slow agility times take away from the big showings in the jumps and the 40 because it opens the door to the question of whether or not he just trained really hard for those drills to make a splash. It isn't to say that there is no chance he turns out to be a stud, or that his agility is a huge deal, but rather it begs the question. It casts a cloud over his whole combine performance, in my opinion.