Evaluating Vikings defensive coordinator George Edwards has always been something of a difficult task from the outside - because it’s hard to know just what his duties are - except we know play-calling isn’t one of them.
We do know that Edwards has had the title of defensive coordinator since Mike Zimmer came to town, and had worked with him previously as well. I suspect Edwards takes the lead in game planning for opponents, and implementing what Zimmer wants done.
But at some point after five years as DC, Zimmer either needs to give him the full responsibility of a DC - including play-calling - or find someone else.