Although there was plenty of response on the Kung Fu Rag Doll survey (if I were to believe this unrepresentative sample, I'd have to conclude that 200,000 people purchased KFRD and that big piles of money were made; I choose not to believe it, though) there wasn't much to the design doc survey.
Here's the thought I keep coming back to. I get the impression from my brief touches with movie people that almost everyone on a movie project reads the screenplay. It's the genetic code for the movie in a way that the design doc never is for a game. Now, maybe this is just one of the many, many ways in which games can not and never will be like movies, but supposing that it is a good thing to have design docs and for everyone to read them, why don't they?
Here are some theories:
A) We don't nicely bind them up and hand them to everybody, saying "Here, read this." Instead we expect people to pick their way through the intricate terrain of the wiki. This is fixable.
B) Design docs frequently suck: they're full of BS; they end up having little or no resemblance to the final game; they're boring. This is fixable. Except for the boring part.
C) Speaking of boring, an interesting movie usually has an interesting screenplay. An interesting game rarely has an interesting design document. This is just the nature of games: it's not the rules of chess that are interesting.
D) Because it's a game, you can't really learn what it is just from reading a document. For example, if this were the design document for chess, would you really learn anything from reading it? It's not until you play it--a lot--that you really know what the hell it is.
E) People are too busy doing their jobs to read the design doc.
F) Screenplays are quick reads. Design docs usually are not.
G) Design docs are constantly evolving - why read them when they're almost instantly out of date? The thing is, to some extent, so are screenplays.
Despite my poorly chosen movie analogy, I do think it's a good idea to have everyone on the team read the design doc: one thing I kept hearing on the last game I was working on was that people "didn't know what the vision for the game was." Even senior guys would say things like, "We really need to figure this system out" - when it had been figured out, and written down, somewhere already.
And I think it's doable: you can address points A, B, E and F. As for D, you still need to do preproduction and prototyping, and have everyone play the prototype. Kleenex testing is a good opportunity for this: has Joe Concept Artist played the game yet? No? Good! We need a kleenex tester.
As for C, part of your design doc usually is a screenplay--assuming you're making an action adventure or role playing game--and there's no reason not to make everybody read that. (Unless it includes *all* the dialog for everything *any* character *ever* says *ever*...) I think we don't do it because we're gamers and we know that the screenplay is really just dressing, but the screenplay usually bears a lot more resemblance to the final product than most of the rest of the design doc does...