It's not about Frazier not being an above average DC, it's about what happens in those franchise steering defining moments.
Interesting point about underperforming D linemen. I've assumed that Epenesa, Boogie, and Oliver are exactly what we see, but perhaps there is a bit more that a different DC and line coach can "Granato" out of them.
Sal/WGR feel McDermott will be calling the D next year on game day. I'm fine with that. We'll see if McDermott can adapt better to individual teams and plays. Will McDermott be quicker to implement Milano to blitz the gap or move up coverage from 10 yards back when the opponent only needs 6 yards for a 1st down? Its' those kinds of things I'll watch. Frazier set a pretty high bar for regular season.