Great thread! One advantage you have is the "body of quirk" of all that's come before. You could look at all that to see what works and what doesn't, and possibly come up with a few guiding principles or rules of thumb.
For example, great quirk ought to be:
1. "Found" not made. I like the idea of quirk as representative of "genius loci," ie it's part of the place - more than that, it's part of what makes the place special or unique, be it man made or natural, like a ruin, cemetery, dune structure, etc.
2. Functional not decorative. If it doesn't affect the play of at least some golfers, then that's not quirk, that's decoration.
3. Likely to produce a result that has some bearing on the quality of the golfer's execution. I think many if not most golfers are willing to accept a level of capriciousness or luck, but most will accept less than what many on here will accept. What the right level of quirkiness is in this regard, I have no idea.
4. Fun in the type of plays and / or results it produces. I think this is the reward golfers who like quirk expect in return for capriciousness. For example the 5th hole at Barnbougle demands a shot hit well left of the par 3 green, but a well executed shot is rewarded not simply with a result that puts the ball on the green, but with the pleasure of watching the ball roll up and around a backstop. Or if not fun, then the quirk should offer opportunities of the heroic variety, like a big carry, shot over a precipice, or eye of the needle (Postage Stamp).
Just my dandruff opinion (flaky and off the top of my head), of course...
Paul, have you seen a book called "Britain's Most Extraordinary Holes"?
You'd love it...
Mark