Ken starts by looking at the World Cup dudes and then CSIA instructors- this section starts at about 16 minutes in and is just the most concentrated voodoo of his vids yet...
Pardon my miss quotes... there is a lot of stuff here.
"Legs are too long as the skis pass underneath. Legs should be long as the ski is out to the side and shortening as the skis come underneath the body. The result is too much up and loss of ski contact with the snow."
" Too far forward stance looses the back of the ski. You can see this is the result of hip rotation.. " ( or something like that )
" Lack of foot separation shows up in too much of a tall stance and the femur is too upright. The inside foot should be forward to accommodate the bend in the legs."
... If you are just going skiing to work on your skiing ...you won't change. You gotta do the exercises of bracquage, javelins, power-plows and hockey stops. "
( how do you spell braccage. bracguage ? anyway )