It's not turn if they remain far more static. The shoulder turn is limited. Turning is an action, not a position.
That's not "casting." That's "coming over the top." Casting is immediately throwing out the right wrist flying wedge (the angle between your right forearm and the club shaft) at the top of the backswing. This swing seems to prescribe not even setting the wrists, leading to a built-in cast.
It can be, but at the end of the day, it's a necessary "evil" if you want to break 90 or certainly 80 with any consistency.
Power.... well you've made mention to me many times about the LPG/ bent arms swing that I've been trying to use. Absolutely no power at all to start with but up until I switched to right hand(to find more power)I was regularly hitting 250 meters with some out to 270. You've said no power often.
If you think we believe you, then... good luck with that. I think we believe that as much as we believe you got a hole in one.
The left shoulder is too far back to have a low point well in front of the golf ball. Margin for error becomes quite thin and fat and thin shots will result. Simple geometry of a circle here.
That's why in the swing video you post the guy (who isn't hitting any golf balls or even brushing the grass most of the time) doesn't leave his head back. He tries to get it farther forward to try to get his left shoulder farther forward.
That video is thoroughly unconvincing. Here are a couple of reasons. Guess which swing this one is:
Answer: it's the one where he is not cocking his wrists at all. Of course, if that was the case, the club shaft should stay close to inline with his lead arm. Oops.
And he says - a few times - that it's "impossible to slice" from the MGS setup because your shoulders are pointed out to the right.
Turns out (pun intended) that they aren't, because like most golf swings, they TURN on the downswing and are, in this case, pointed well to the left.
I'll also point out that he gains a fair amount of clubhead speed the farther he moves away from MGS (and that thing is probably measuring km/h - also, it's not measuring at any particular point in the swing - so if the max speed is three feet AFTER impact, it won't matter to the speed stick thing, but it matters to the golf ball), that he re-centers the head a good amount after making the backswing, and that his feels aren't real. He's not hitting a golf ball, we can't see his divots, and he's marketing himself based on someone else's ideas. It's a whole crop of pseudo-science and "feel ain't real but we're gonna market it like it is" that appeals to some counter-culture idiots who think there's some secret hidden path out there to playing great golf.
There's not, because if there really WAS a way out there, the first guy to teach it would be wealthy, PGA Tour players would be using it, etc. Instead, you've got some person or small group hoping to sucker in a few delusional people to milk them for some money. There's an endless supply of suckers, as they say, so it's not necessarily a bad business practice. It's just not a good golf practice. It's built upon the fantasy that feel IS real and ignores basic biokinetics/biomechanics, certain laws of geometry and physics, and so on.
Tiger Woods could kick your ass (or this guy's ass) playing with a set of women's clubs left-handed with one hand on the club (and you can pick which hand).
Now, logman, claim it as a victory if you like, but I'm done wasting my time looking at videos or doing the little bit of reading I've done on this. You've presented no compelling argument or idea. It's not even "your" swing. So I'm done wasting my time.
P.S. Man up. Post a video of YOUR swing sometime.