It was worth it though. After I sobered up a little ([wink]) I was chatting to people in #gamedev and I got into a little design brainstorming session with aboom. He was trying to use CRC cards for... well, I'm not entirely sure what for, but he hadn't done much formal thought about his game design other than "BF1942 clone." I fired a bunch of questions at him, and we started hashing things out a little more - destructable objects in the environment, camoflague, and a versatile radio system got discussed. I'm pretty confident that the set of gameplay elements he's now thinking over would allow for some solid gameplay (with the appropriate level design, natch).
Consider this: Every gameplay situation is the result of some combination of game elements. That's kinda like the description of a vector space, no? Every elements in the vector space is the result of some combination of the basis vectors?
It leads me to wonder that an effective design technique might not be to start with a collection of gameplay situations, from which you derive your 'basis' gameplay elements.
I suppose it's sort of like user story driven design.