Which raises two questions: 1) What really are "the fundamentals"? 2) Are coaches/instructors who are limiting the use of these sorts of skis because of "the fundamentals" doing it for the true benefit of their customers - or because they can not or will not leave their own comfort zone?
Perhaps if you live in PNW and only ski on fresh days, a rocker ski is all you need. I consider that limited-use.
For other uses, conventional skis, big or not, apply.
Fundamentals are fundamentals. That's why they call them that. It's what you do to ski.
Sage, Seth or Shane likely learned a few basics before dropping into 55 degree slopes.