While I agree with your goal of finding analogies when teaching new concepts, I think your first paragraph is a pretty unsympathetic take on music theory. (I don't know anything about photography.)
Music theory is descriptive, not prescriptive. Is it any surprise that something we had to invent a whole new symbolic notation for is difficult to connect to concepts we can describe in natural language?
If you want to go really deep into the philosophy of music, to understand it from "first principles" so to speak, I highly recommend Leonard Bernstein's lecture series "The Unanswered Question" - https://en.wikipedia.org/wiki/The_Unanswered_Question_(lectu... (available on YouTube).
To paraphrase Bernstein's comment from his book "The Joy of Music": we need to stop comparing Beethoven to grassy fields and mountain streams. A "major seventh" or a "plagal cadance" are themselves the description of those qualities. By all means use music as metaphor, but when you're trying to describe it you're going to be using terms specific to its domain.
