The backcourt is doing its job- slowing down the ball handler and mostly funnelling them into specific areas late in the shot clock. It's not so much overrated as impossible, especially with all the targeted quickness training and no-handcheck rule. The responsibility lies mostly on the bigs, as they are either: 1) Not carrying their end of the P&R Defense or 2) Just plain not mobile and/or athletic enough to contest shots well.
It looks to me that Stevens wants an aggressive "never go under," attack and disrupt the ballhandler P&R defense and the guards adjusted while the bigs are still stuck in last year's system where they'd go under and take away drives (which is unaffective due to the guards going over and the increase in space to work with for the ballhandler).