first of all, congratulation to this cool pages

i really enjoyed the pics & movies.
regarding the technique description, i would not, out of personal experience, agree that it is the angle of the bindings and the size of the board that is the responsible for the bad technique of the majority of the snowboarders.
why this conclusion? personally, i am an extreme carver on skis & skwal. and i have made the experience that it is very well possible to do extreme turns touching with the whole body the snow with a skwal.
the technique to do so is, of course, sligthly different from the technique that you are (very successfully

* either just "dive" to the other side (the rotation implied by this movement is just enough)
* or you push yourself up to "fall" to the other side
the technique on the skwal appears to me a little bit like the back turns you are describing, with the difference that i apply the pressure not with my heels, but with the side of the foot.
these movements are, if you are coming from extrem carving on ski, very natural.
Regarding to your statement that body movement should be as scarce as possible, i completely agree with you, as well as with the fact that counter rotation is the "death" of all technical progress (also on the skwal).
kind regards
m