Good post, well stated.
I also liked what you said. It seems to me that the classic doctrinal formulations are, in a way, cautionary. That is, if I find myself in a line of thought that divides the substance or confuses the persons -- or in Christ confuses the natures or divides the person, I'm probably messing up.
One of my favorite moments in my education happened when i was tangling with one of my best-loved professors and I said, "You're dividing the person!" and he laughed and replied, "I am NOT -- YOU'RE confusing the natures!" And we both laughed.
Mind you, we both used to go around muttering at each other, "None is orthodox but me and thee, and sometimes I have my doubts about thee ..."