Ball contact sounded really good - I'd say that if you're a really low handicap- then you've got a nice pattern. However, if you're not a low handicap or would like to improve, then looking at the face on video - see how much your rehearsal looks like your full motion/power swing is what I noticed. Need to start to improve that rehearsal move to make some important changes 1) Notice the right wrist flattening out, 2) Notice hardly any weight shift (sliding hips), looks like your grooving two bad things in your swing - with that practice move. As a result- notice the flat feet through impact and no hip rotation through impact, with the right wrist flattening, the left wrist bending and the left arm folding- all at impact but notice-able shortly after impact.
From behind- tied in with the early release- do a frame by frame as you finish the backswing and start the downswing- see that odd move where there's either an uncocking of the wrists or you're moving the hands further away as you start down.
A) Don't hit off of matts- find some grass where you can take a divot.
B) Work on the pre-rehearsal of the downswing- the hands go down and forward- with the right wrist bent and the left flat- as a result the hips slide and then rotate.
C)Check yourself on video.
Just for clarification- I wasn't trying to be funny. The better the player the more variations I would allow. That's why I wanted him to let us know his handicap, etc. No sense changing Lee Trevino's arched left wrist at the top- if he's got a pattern that works well.
Now, it's just me but if the same player had a Lee Trevino looking swing but was a 40 handicap - then I would try to make it more conventional- simpler. Likewise, I'd be a little nervous or careful about changing a component in Lee Trevino's swing- I'd rather have him understand the components in his swing and realize where things might go wrong- or how all the components add up or offset to produce good golf shots.
So it's a combination of how well the pattern's ingrained and how proficient the pattern is - that would determine if you want to change it- ofcourse, combined with the goal of the student.
Great points Mike. This is where the Artist part of being an instructor comes in. You must know what to 'fix' and what not to fix, and there are no fixed rules.