Theory: Building a swing from the inside out

I'm starting to have a theory about how to build a swing.  After a year of constant and intensive experimenting I'm starting to think of how I would try to build someone else's swing.  Once all the real basics are covered like grip, address, etc.  I think you should start with a close examination of the impact position while hitting balls.  Is the wrist supinated, scooping, hands infront of club face, laid off or not, etc.  I would then correct that first because I think that the body compensates in the backswing and downswing for the improper wrist/hand positions at impact.  I think a lot of people cast to close the club face and not because they want to hit at the ball like most teachers say.  So just having them layoff and supinate their wrists more throughout their swing will then tell their body that they don't have to cast anymore to make the ball go straight.  Changing wrist positions is a lot easier than trying to get your body to sub-conscientiously react a different way.

I'm also starting to think that most teachers work from the outside in (address, plane, backswing, downswing, follow through) and they brush over impact.  The reason is quite simple in that you can only give feedback on what you can see.  And since they can't see what's happening at impact because it happens too fast they don't know what's happening with the wrists.  But they can see everything else so that's what they correct.  The poor students are compensating for a bad impact position in their backswing, downswing , etc.  to hit the ball straight.  And the teacher tries to correct the compensations and not the root cause which is squaring the clubface at impact.  With the high speed camera you can see the wrists and club face.  The root cause of the bad swing.