Dan, would you be open to discuss the "structural flaws" ? and under what circumstances would those flaws expose? thanks.
Well I think everyone has their own opinions
There are too many to cover well, but Major ones IMO:
Shoulder driven power; lifting, separating, pulling or drawing down, (easy to see, easy to read easy to overcome and manipulate)
Hip driven power (easy to read in fighting and the basis for most throws)
Tight groin and hips (see above)
Not moving from the center (which makes it easy to read you while fighting as you constantly have to shift, one side to the other to fire-off anything; kicks, strikes, throws)
One side weighted (see above)
Not understanding central axis and how it supports itself in unified movement
Turning from the hips (although it is used in ICMA and many of the new JMA as well)
Extending or pulling-in, in unsupported single-side muscle driven movement with the hand and feet on the same side to power which opens you up for double weightedness
Always using the elbow and hand together
Always using the foot and knee, together
Isolation in movement
Not understanding how to use the body to counterweight itself under various pressures in all angles.
Tucking the sacrum (personal opinion, I think it is leaves the body vulnerable and there is a better way)
Letting power into your structure at contact points then training to physically move your whole body around it, as well as letting power in and then...tying to manipulate it after. While these are more of a "use" issue, there is a conditioning method to change how you manage force, so I would place it as a structural weakness or vulnerability for a lot of people as they just could not switch over by choice.
Mind you thats just my opinion