There are many reasons why it is so difficult to progress from being a good skier to a truly great one. Firstly, there are very few individuals on this planet that have the inherent abilities that elite athletes possess. Mental strength and physical co-ordination are not born in all mice and men. Secondly, people are not committed enough to make the changes in their skiing work. Any change WILL feel weird and will do so for a while, but you have to persist with it. Therein lies the lack of discipline that makes it very difficult for individuals to improve.
Not everyone that picks up a golf club becomes a “scratch” player, so why should we expect the same of skiers out there, particularly when you include restrictive equipment and, of all things, gravity.
As far as the boot discussion goes, IMHO, getting the basic mechanics of skiing working well in a student, is far more important than whether or not they are 1.5 degrees out of alignment. No offence, but I feel this is a “forest for the trees” scenario.
Just in case you were wondering, I am a former ski instructor who did 20 winters back to back in Australia, Canada, Austria, Vermont, and Utah. Whereupon, one of my 30 – 40 days a season clients, offered me a position with his firm in Austin, TX