There is a LOT that can be trained with plain old muscles and the nervous system, for instance:
1. Get every muscle from your toes, fingers, wrists, neck, ankles, forearms, calves, various rotators of the shoulders and hips, the abdomen, as well as all the major extensors/flexors involved in every movement, and working in biomechanically efficient lines and rotation around axes.
2. Get them all activating simultaneously/instantaneously (without any preparation or delay) and with equal intensity.
I think that the fascia must be very useful in the two things you describe above in that it can transmit instant awareness among all the areas of the body. Dan has refered to it as a "load distributor system," I think--meaning that it can diffuse impacts by spreading them through the system and that it can sort of "govern" the work of the entire muscle system at once. I think it also can "manage" the efforts of the whole muscle system so that each muscle contributes the optimal effort to the whole effort.
In any case, if your body has an entire different system, why leave that out of the equation if you're looking for "total" effectiveness?
4. Keeping all of the above, get them to activate and then release in an instant, like an electric shock. Two aspects: minimizing transition trime from relaxation to tension, and from tension to relaxation.
If my above ideas are correct, the fascia would also facilitate those efforts.
Since my sudden recognition the other day, I've been having a pretty good time working with a new level of feeling. I've also been thinking a lot about "how" you could apply this system and a lot of what has been said on these forums has come back to me. Also, there is a lot about the fascia system and the nerves connected to it that has not been discussed at all, including emotional states and involuntary responses, that I think would have a lot to do with managing stresses.