On the Jim Suttie study I linked to, one key difference there was that they had a pump move to start the downswing, which likely increased power.
However, I also think there are flaws there in that study. They only had 29 golfers in the study, which is really only enough to give valid results for the group as a whole, not for subgroups. But they don't really give any results for the group as a whole. Instead everything is broken down by handicap, without saying what the sample was for each subgroup. I also notice that even the single digit handicappers in that sample only had an average carry with their 5-iron of 130 yards. So I also suspect it may not be a representative sample of single digit handicappers. Finally, while the study shows only a small loss of distance, it also shows minimal gains in accuracy either that I can see.
Now it may be that there are real gains for some golfers who practice this for some time (rather than learn it and take a few swings right away). But I suspect this is still mainly for people who don't already have a good swing. It seems like it might be especially useful as a kind of drill for golfers who haven't yet learned to make good consistent contact (simplifying everything else helps to focus more on impact).
Even looking at the Kinwar videos though, it seems none of her students who are actually good golfers really even use the whole swing; most of them seem to still be using a normal wrist hinge rather than going verticle with the club at the top like she does. And in the Hooters tour players video posted above, she only had the players increase the right side tilt, they didn't do anything else that she teaches. So this is essentially a video on the benefit of having and maintaining good secondary tilt.
Finally, as for the biomechanically correct swing, it seems to me there was a guy named Mike Austin, with a degree in mechanical engineering and a doctorate in kinesiology, who did that years ago and managed to generate a little more power with his version.
I have the little wrist 'thingy" that one of Mike Austin's biographers, Philip Reed, markets. Interesting. It makes a golfer perform an underhanded clap or skipping stone motion and encourages the golfer to fully load the trailing side of your golf swing with a head tilt and lower body step as a downswing trigger.
None of Mike Austin's group however, tries to pretend his method is easily used by common golfers which seems to be Kiran's design and purpose. Keeping the right side in tilt is her "magic move" and certainly has helped my swing even with a deteriorating physical condition! Tomorrow I'll hit balls somewhere and I am eager to see how many benefits come from this simple MGSS.