Always seems to come back to coordinated mind and body.
Pretty much. I don't think many would disagree with that basic concept. I think the on-going debate circles around presenting the attributes of the different training models each person is familiar with.
When I formulated my definition of Ki, I based it on the three harmonies model, "mind leads intent, intent leads Ki, Ki leads power", which is one of the bases of how I like to train. I tried, however, to place the definition closer to the realm of physical reality. Since "spiritual energy" is not a defined type of energy nor can we measure its sate, I used "physical energy" (resulting from our tangible body mass), which can be transformed into either mechanical and/or thermal energy, and finally expressed as power (energy/time), the process being initiated by the mind or as some call it "intent" (which follows a desire).