So am I mistaken to think that you train and spar full force with no pads and anything goes - like a real street fight? At my dojo our Yakusoku kumite is not just a patty cake back and forth motion. We do specific drills yes, but we also hit hard and take hard hits to all parts of our body without pads. This helps with conditioning. The limited area is to the face and head due to insurance reasons. That is a reason we don't have free sparring or full contact. My students train hard and do get hit.
You also said, "This SHOULD then lead up to light contact free sparring to test those principles and body positions in a more resistant environment. The final stage is full contact fighting to gain an understanding of how to utilize the techniques against a fully resistant opponent."
I would like to come to your dojo someday to see this full contact free sparring. You either must not have insurance or you must have very disciplined, controlled students for serious injury not to occur. I think I am assuming that you and your students go all out and act like a street fight. Or am I wrong?
You also said, "Without this progression the practitioner fails to understand or is not properly trained in true timing and the dynamics of what it feels like to get hit full force." True timing can be learned through what you suggest and also what I teach. You do not know exactly what happens at our dojo. But I think that a surprise attack or multiple attack or a different fight environment can disable someone's true timing very easily.
How many of us train outside, in the dark, on uneven ground, in an enclosed space etc. and not just in a big well lighted open school?
Do most fights happen in your dojo? I doubt it.
Sorry if I rambled a bit.
Imperial Crane Martial Arts