I've got to put in a couple of points here: first, a little bit of PMTS goes a long ways and second, HH's injury was the best thing that happened to me this year!
As to the second, having HH around the forum lending point after point of insight and advice on a regular basis allowed me a few modest but crucial breakthroughs this year. In particular, this thread was key. Hopefully, I will not need for him to be injured in the future in order to be a better skier myself.
But as to the first, while the goal of PMTS is to be an "expert", just getting some of the essentials even halfway right seems to make a huge difference. And I measure "difference" not by how "pretty" I ski (not very, I suppose) but by the range of conditions I can handle and at what level of effort it takes. I can report I've made significant progress in torn-up half frozen garbage with relatively little discomfort. I think the keys were much better transition with better tipping and lessened push-off plus moving by hands and upper body by moving my hips rather than the torso (i.e., real CA).
I know by essentials aren't "there" but I'm thinking I'm starting to get the building blocks upon which maybe a foundation can be constructed. But the bottom line is that at least going down the PMTS path will do you good: you don't have to perfect it to see real results. (Perception/reality understood).
But I'm thinking that there should be one more "essential". And that's the "confidence" thing that has been brought up. I've found that the only real way to "make" an essential movement is with confidence and authority. Since these movements are definite "changes", you have make them with conviction or they just won't happen. This is especially important when strutting your new moves in challenging conditions. More than once I've been skiing well in stuff I've had problems with in the past and just for a fleeting moment thinking "what are you doing here?" Boy, can that be trouble!
While I'm on the topic of PMTS "benefits", let me add another: your own safety and well-being. I've always known that the PMTS progressions are "safe" in that the student is never in a position of losing control or getting into the highspeed "Wedge O' Death" of TTS. But when I was skiing in the junk with a TTS instructor (up-move city) he was saying "maybe we should stay away" from the heavily tree-lined edges. Upon reflection later I realized that in PMTS if I was aiming towards the edge I was already tipping and rolling the skis into a turn. The worst that could happen was a feet-first slide off the trail, not a head-long crash because something went horribly wrong in an up-move transition.