Pat,
It's an interesting argument and as such attracts counter examples, but that said, I think it is largely sound. Boiled down, variety in clubs is a proxy for interest, so, yeah, better than not.
Are there (5) courses in the world with straight holes that measure (D) + (PW) + [iron gap yardage] * 0..10? For the sake of argument, if you ranked the World's courses from top to bottom, I would bet there are 5 within the bottom 20% alone. So, if you take your thesis strictly, we can all imagine a cow pasture that meets the hypothesis but fails the conclusion.
That said, if the Par-3 course at Bandon extracts every club from your bag, or any Par-3 course of enough holes, would you grant that it is good GCA?
Dave