this is completely beyond me
Well, TomB, I'm afraid I'll have to agree with you on that. Like I said before, these are things good instructors work very hard to understand, things unlikely to be obvious to someone without their background. Indeed, cause and effect are rarely obvious. People often seek out instructors because they've become aware of something that's not working in their skiing, but that "thing" is almost invariably an effect of something else, and it is the instructor's expertise that lets them get to the bottom of it--to the "root cause"--and find the key to improvement.
Please keep in mind that almost everything here is conjecture about Skisalot's (original poster's) skiing, since we have not actually seen him ski. But from his description, there's a pretty good chance he looks a lot like the skier in this brief clip:
You may (or may not, if your eye is not sharp) observe that, like Skisalot, this skier falls to the inside (uphill) ski in the second half of his turns. As you have correctly suggested, Tom, he "banks" (meaning he inclines his whole body into the turn with little to no "angulation") and his position at the end of the turn is "square" (body facing the same direction as his skis, no "counter") or slightly rotated into the turn.
The problem this skier is likely to observe is that he falls to the inside ski in the second half of his turn, as his skis skid a lot. Almost anyone can see that he has little edge angle in the second half of the turn, and if you're a bit more knowledgeable, you might surmise that the cause is that he is "banking" (inclining into the turn with his whole body, with no "angulation"). So you might--as you have, Tom--suggest that the solution is to tip his upper body downhill over his outside ski to create some hip angulation, thereby shifting his balance out over the outside ski and increasing his edge angle. Congratulations--you have a rudimentary understanding of cause and effect. But your lesson would fail.
A slightly more experienced instructor might notice that a primary reason he has no hip angles at the end of the turn is that his body position is "square" (body facing the same direction as his skis, no "counter") or slightly rotated into the turn. Keen understanding of cause and effect leads you to know that a square-to-rotated position like that actually causes the hips to move out over the skis, precluding the possibility of hip angulation. So you might suggest that he needs to add some "counter" here--twist his upper body down the hill--which would indeed put him into a position from which he could then create some hip angulation, balance over the outside ski, and increase his edge angle. If you see and understand this, congratulations again--your understanding of cause and effect is above average. But your lesson would still amount to no more than a bandaid patch of the symptoms, while entirely missing the cause of those symptoms.
A superior instructor would recognize that this skier's lack of counter and minimal edge angles at the end of the turn are caused by the movements he uses to start the turn--in particular the "rotary" movements. Note that he begins each turn by twisting his arms and upper body into the turn--a movement pattern commonly known as "rotation" or "upper body rotation." This movement pattern at the beginning of the turn causes his later-in-the-turn problems. That's right--his edging and pressure control problems at the end of the turn result from rotary problems at the beginning of the turn.
You cannot "fix" them by focusing on the effects at the end of the turn--where the skier notices them. You've got to identify the cause and address the problem there.
So his "problem" is upper body rotation to initiate the turn. The solution is to develop a new movement pattern to initiate the turn. If he needs (for whatever reason) to turn his skis as forcefully as he does, he will need to learn to do it with his legs, not his upper body. Turning his legs in the hip sockets, beneath a stable pelvis and upper body, will result in the countered alignment that will enable him to angulate and balance on his outside ski throughout the turn.
And a great drill for developing the skill of leg rotation is Pivot Slips. They also develop the related and critical skill of releasing the edges--letting go of the mountain--prior to steering the ski tips into the turn. The upper body rotation, as you can see in the clip, causes the ski tails to twist out of the turn into a skid, further contributing to the problem of falling to the inside ski. If this skier (and quite possibly also Skisalot) were to focus on starting his turn by releasing his edges and guiding his skis into the turn, rather than setting the edges (which he does at the very end of each turn in the clip) and pushing/twisting away from the "platform" of those set edges, it is very likely that the problems he observes at the end of the turn would vanish.
Of course, the truly superior instructor would not stop there. Why does the skier use upper body rotation to start the turn? Was he taught that way? (Many were, especially if they learned a long time ago, or if they were never introduced to the movements of turning their legs without the use of their upper body.) Is he defensive, and therefore trying twist his skis around quickly to avoid gaining speed (very likely)? A truly competent instructor will continue to work back to identify the true root cause, and address the problem there. Fix the cause, and the effects (symptoms) will take care of themselves.
On a side note, it seems likely, Tom, that you may not really understand what Pivot Slips are--and what they are not. Far from leading to skidded turns, they develop the "release" and feeling for "neutral" that are the key to NOT twisting the skis into a skid (as the skier in the clip does). You are not alone in this misunderstanding, of course. It is natural, because Pivot Slips are, themselves, far from carved turns. They are not turns at all. They are simply a drill that develops the skills and sensations of the transition and initiation phases of turns, along with the ability to control the skis precisely with the legs, not the upper body. They have nothing to do with the "pressure," "carving," or "shaping" phase of the turn.
That video clip represents a very common syndrome of movements in recreational skiers. No one here--except perhaps Skisalot himself--can say for sure at this point how relevant it is to Skisalot. But from his self-description, I'd be willing to lay pretty good odds that his "problem" is similar.
What do you say, Skisalot? Do you see any of yourself in this video clip and description? Of course, if you have any video of yourself, we could sure eliminate a lot of guesswork!