Check out 'The Adventure' chapter in the 1E PHB. Players are educated here about the possibility of traps of various types that are designed to injure/kill, confine, or channel thier characters.
None of which addresses my point.
The nuts and bolts of trap operation was left to the creativity of the DM.
Indeed. Now
that is my point. Alot of things were left to the creativity of the DM, and if you had creative DMs of excellent judgment and good rules smithing ability then so much the better. But the problem here is that at some point, you can't claim that you've left things entirely up to the DM and also provided a complete set of rules. If you could, then the following is a complete set of rules:
"Make something up."
There, I've condensed all of D&D to 3 words, much less 200 pages. So at some arbitrary point I think we both agree that its not complete until you've provided more flesh than "Make something up." We might not agree exactly what that point is, but I think we agree it exists.
One could run traps just fine without ever looking at a published module. The idea of needing every minute detail of game mechanical operation spelled out in black and white is a more recent one in rpgs. Left to think for themselves, DMs came up with all types of interesting and creative ways to mechanically run traps.
Or, they didn't. I suspect we'll find lots of people who hate traps as a concept precisely because they didn't agree that thier DM always came up with all types of interesting mechanics for running traps. And I think you are vastly underestimating the reliance the average DM had on published examples of traps to nudge them in the proper D&Dish direction, or even the amount of agreement you'd get that published modules always handled traps in mechanically interesting ways.
Talking with other gamers back then I don't recall a lot of hopelessly lost DMs who had no idea how a trap was supposed to work. I suppose the reason for this was that there wasn't a rulebook set suitable for weightlifting that spelled out the 'right' way to do things.
No, I suspect the reason for this was the vast amount of supplemental material that was published on the subject of traps and communicated orally to players by DM who had prior experience with the published material (directly or indirectly) in lui of having it spelled out in some official examples. I think you are dealing with a fairly large and complex body of assumed and effective rules which weren't formal written rules. There is a very difficult question here involving supporting a new player. What supports him better, "Silence on a subject in order to keep the size of the book down, or addressing a topic so that he has some actual rules support at the cost of increased scope of the rules"?
I am, once again, pointing out that defacto rules of play ('house rules') are at least as burdensome on play as the formal written rules of play, and for my money they are more burdensome because no one necessarily really has a clear idea of what those rules are. When you leave an area of the game to 'make something up', you are saving paper, but you aren't necessarily making the game simpler.
Plus, you are ignoring that over time, as more supplemental material was published and more and more tables house rules converged (by using the supplemental material) that the scope of what people considered 'D&D' necessarily increased. Critical hits are a good example of this. So is weapon specialization. So is the barbarian class. Third edition tried to capture all the idea people associated with 'core D&D' in to its core rules, even where the rule itself was not a core rule of the prior edition. The rules expanded because the earlier editions were percieved as 'incomplete'.
