[tongzilla]

I agree with you that amateurs have it all over the place.Does the flat left wrist fix this fault or is that too simplistic?

I'm not a teacher but I see this all the time with higher handicap players and how would you go about fixing it?

Typical profile of a good hacker:
Strong left hand grip, bent left wrist at the top, outside in clubhead path.

Fix:
First fix everything that looks very obviously wrong, e.g. stance is aimed 40 yards open, spine angle vertical at address, head opposite left foot at address, etc. Then flatten left wrist at the top. This should result in hooks and pull hooks, especially if the student knows how to finish swivel properly. Then neutralise grip. Then fix the clubshaft at the top and startdown.