It's not all on the players when your passing D yards allowed ranks #127. Candy and Arky were the only two in the SEC in the same range. We were the SEC's version of UNC in the ACC.
We have a lot of players that a lot of SEC schools wanted who have better D's and secondary coaches/DCs. The talent was back there. Many SEC schools had lower rated roster talent and had better passing defenses.
There is a factor to consider that says more passing yards are a result of having to defense more plays due to our O being tempo that gives each team more possessions. The exception to that argument is that we give up more plays per drive than normal because we could not get off the field. Our rush game D was #19. They also had more plays to defense than norm. Yet, they got it done.
The scheme of getting to the passer quickly to help on the back end did not work well enough. It appeared at times that DC Banks even forgot that plan, which caused part of the problem.
Our O coaches were exponentially better at their job than the DC and secondary coach were at theirs. Our DL/LB/OLB coaches were better on the defensive side of the ball, but did not get enough done due to scheme and play calls to help the passing defense. It's in the stats.
It's really that simple. That says if Heup stands pat with D-staff another season they better perform better as coaches, which they may. Will see. I would not be betting my career on it, but that's Heup's to decide and he's the man.