As always, the ideal is to identify the movement patterns of expert skiing, introduce those exact movement patterns to beginners, and develop and improve the skills at those patterns at every level. That is to say, the very same movement patterns on green, blue, and black terrain.
But that's just the beginning, of course! There are many movement patterns that experts master--and use, depending upon their needs and intent. Skiers of all levels operate on the same intents. That is, sometimes they're trying to stop or slow down (defensive intent); other times they're trying to control their line, and go exactly where they want to go (offensive intent); and still other times all they're trying to do is play with their equipment and the mountain, feeling g-forces, weightlessness, or carving turns. So we need to introduce to beginners, and develop at every level, the various movement patterns that match these various intents. They're all important.
One thing that has not changed, and I can't see how it's likely to change in the near future, is the fact that there are three, and only three, things you can do to your ski with your foot: you can turn it left and right, tip it left and right, and push and pull on it, in various locations. So skiing is, always has been, and presumably always will be, a question of developing and increasing skill at these three things--rotary skill, edging skill, and pressure control skill--and blending these movements in various ways to facilitate our needs and intents.
It is true that intent, and therefore also the movement patterns dictated by intent, may change from green to blue to black to beyond. We all have our thresholds of comfort, where our state of mind goes from offensive to defensive. A skier comfortable cruising offensively on green terrain may very well become defensive and "brakey" on black terrain, and his/her movement patterns will certainly change when that happens. But I didn't get the impression that that was your question.
So I guess I'm really not clear just what your question is. You said, absolutely accurately, that the movement patterns of good skiing "thread through all levels of skiers." This implies that they change quantitatively (more skill), but not qualitatively (they're fundamentally the same), with ability level.
I don't know if this furthers the discussion or not!