Kool has had some excellent production units with some of the most unathletic lineman you'll see. Check out my posts about how unathletic and not special our DL has been over the past three seasons. Lots of 2, 3, 8 percentile athletes.
Then you look back at Mizzou...Michael Sam was a terrible athlete, Shane Ray and Markus Golden were way below average athletes. Kony Ealy had bend but not a great athlete. Sheldon Richardon was a hoss, but really, the only stud and superathlete he's had. Lots of guys that ultimately are average or non-existent NFL players. You can now add Quinnen Williams to that list. But also add Isaiah Buggs (1 percentile athlete) to the other list.
Smart men can disagree...but, I'm just saying he had done a lot with some really poor athletes in his position rooms.