You said how it was on coaching:
I didn't mean coaching as far as scheme. I meant coaching as far as being in the right place at the right time. In this play, one UNC player took out two defenders which looks like one chose the wrong gap. CPJ has said variants of "we're asking our defensive players to do too much," similar to what Groh did.
If there's any case for keeping Roof, it is that he would make a marked change to preach execution and have a simpler scheme. But the 2014 defense had similar issues to this defense. In the UNC game that year, UNC had a long throw against man coverage which should have been a sack but the blitz went to the wrong gap.