It has been beaten to death but its a very good case to look at for understanding why the previous skill concept failed us. Rotary is part of skiing, even for pmts skiers that refuse to admit it. HH created such an objectionable point about rotary because skiers all over the mountain are over using it. PSIA did not specifically define how to use rotary exactly. Different coaches an trainers have all come up with their own ideas, sometimes shared and sometimes not, but what I can say is that the lack of definition is why rotary is being terribly over used and over taught by many.
HH's demonization of rotary is in direct opposition to that "problem", and understandably so. The disappointing think for PMTSers is that they also have no definitions for this aspect of skiing. They are taught to try to rotate as little as possible or not at all, and generally if I have to choose, I will choose that too for a variety of reasons, but nonetheless I know that when I ski, while I am avoiding pivots before edge set most of the time, sometimes I am darn glad I know how to pivot. And turning the feet using rotary skills, simple to keep the legs out of the way of femur skis is an important aspect as well in my view, as well as contributing to steering. So I feel PMTS ha also dropped the ball on that skill set. But so has PSIA. Neither one of them have identified and defined specific ways to utilize rotary. One says use rotary to turn and has resulted in far too many pivoty skiers that don't know how to shape the top half of their turns. At the other extreme we have pmts mindset which doesn't officially support any kind of rotary at all. In my view they have both failed to define this skill area
In general, BTS, I agree with the large majority of what you write but I think the above perpetuates a misunderstanding. There is as much rotation of the femur head in the hip socket in HH's skiing as there is in any other elite skier. This is created by the action of the skis on the snow and is controlled primarily by edge control and pressure. The rotary skill advocated by PSIA consists of advice to twist the legs in the hip socket using the leg rotator muscles as an intentional, active focus of a basic turn.
There are those who argue that these two descriptions are the same and that, for all practical purposes, the movements are indistinguishable. I don't agree. Nor do I think that it is never necessary to wrench one's skis around. Sometimes it might also be necessary to take a nose dive into the snow - if the only other alternative is to ski off a cliff for example. But these exceptions are not part of a "perfect turn" and shouldn't be taught as if they were.