Bon Jour Benedict, and thank you for your kind words.
I think you're probably right about including more theory in piano instruction ....
Here's a story -- wonder what you and others make of it?
Some years ago, my piano teacher (and close friend), his wife and I drove to my home town and had dinner with my parents. Also invited were close family friends and their two children, who were all good musicians.
After dinner, my teacher (a truly great artist IMO who has been quite successful concertizing) played several pieces on our Baldwin Acrosonic.
While playing the Chopin etude in c sharp minor (the very fast one), he suddenly stopped near the top of the keyboard, hands in mid-air! INSTANTLY the daughter of our family friends, who was watching, yelled out, "D". [She had studied piano since 3 and had just been admitted to Juillard.] My friend who was playing laughed, said a sincere "Thanks!" and without any trouble continued playing the piece.
Even with pieces I know by heart, I would not be able to yell out a chord name if someone else were playing and got stuck. Nor would I be able to recover instantly, if I were playing, got stuck and someone else yelled out a chord.
The daughter who yelled out "D" told me a few years later, when I studied with her, that she memorized the chords (by letters) of her pieces. I've never done that ... maybe I should?
Well, what do you folks make of all this?