Such as? (interested in what you think are the key elements that make D&D, well D&D)
Well, it's a bit complicated. People now tend to judge 1E by
strictly modern terms. They don't judge it in the context of the times in which it was actually produced. In particular it is judged based quite harshly in terms of its mechanics. But in many ways I see the mechanics as the EASY part and yet each new version of the game seemed to be more and more about changes in the mechanics and less and less about the rather strange and revolutionary idea of assuming the role of a character. It's not just moving your game piece around a board or table-top like a rook in chess or the dog in Monopoly and saying, "That's me!" This is a game where although there needed to be some rules about what your character can and can't do (mostly revolving around combat resolution) you were largely UNconstrained in decisions about what your character might do and say. And the Dungeon Master generally assumed an even GREATER freedom in deciding what monsters and NPC's could and would do in response.
But those mechanics seemed to consume more and more of the focus of the game rules. 3rd Edition in particular is where I eventually saw there had been a break. WotC patterned its creation and support for the game after its collectible card games where there was nearly ALWAYS an official rule. Their response to D&D game questions - to RULES questions - never started with, "Do what you think works best," but with, "Well here's the OFFICIAL response which is mostly a longer rule, or more rules to add on that will replace a problem in a rule." And maybe just occasionally a suggestion to actually make it up yourself rather than be paralyzed in the absence of an OFFICIAL response. Yet when I finally tired of 3E and went back to reading and re-reading 1E I kept seeing ADVICE, not RULINGS.
The 1E DMG in particular was bookended by author statements that amounted to, "Make it up. Don't let ME/US tell you what to do, and certainly don't let your PLAYERS start holding game rules over your head saying, 'Thou shalt not deviate because It Is Written'." Those statements are, sadly, lost in the size and insufficiently organized nature of the DMG but I have come to see them as VITAL elements of the original game. Elements which made it what it was, and which have now been largely written out of the game in favor of always seeking more rules, or more clearly written rules. Rules which will prevent as many adjudication moments as possible from arising in the first place.
Hey, I may be wrong but I've now had
30 years of edition debates and I no longer care to really debate it. I'm only expounding here because you asked. I would simply rather be playing AD&D, warts and all, even with its sad cries for better mechanics than to play more recent versions. I can and have replaced those mechanics I found most wanting and I continue to enjoy the DM's task of always SEARCHING for better mechanics. But mastering those mechanics or perfecting them is not the game itself.
A certain amount of rules mastery as part of the game is to be expected simply because the game is of such a large scope. THAT is part of the fun orginally because it could reward players with benefits for their deeper interest and investigation of the rules. However attempting to intentionally design the game to REVOLVE around rules mastery was a serious error that the game has yet to recover from. It seemed that someone missed the subtler point of mastering rules and assumed that the more rules there were to master then the more fun it would be for everyone. But mastering the myriad and complicated rules wasn't the point of the game. So the focus of the game shifted to RULES and away from that idea that it was fun simply pretending to be someone you're not. Every superior, tighter, more elegant mechanic written into a new edition also carried with it a small but cumulative loss of things that made the game fun and popular in the first place.
