BVG was most certainly NOT running an NFL defense.
He was taking one package of an NFL defense (nickel and dime in passing situations) and trying to install that as his base scheme. It is easy to exploit and it was foolish to run it.
The problem in 2014 is that there was no "base" scheme to return to; since it is all based on packages and reacting to the offense, when you have younger kids in the game that aren't as quick in recognition they are going to struggle getting lined up. Getting lined up on defense should be the easiest thing to do--identify the strength and the formation and go to where you need to be. Should be almost instant recognition. That it was taking so long and guys were so out of position is damning. The fact that the defensive coaches were retained for 2 more years is an indictment of the decision makers, specifically the head coach and the athletic director.