In the 1970’s and early 1980’s, the focus was clearly the dungeon as the place where the adventures happened. From the early articles in The Dragon (ah, I remember well when it still had the “The” in front of the name) to the advice to players contained in the Players Handbook, things were clearly geared towards the notion that there would be a large stable of players who would come in and out of the campaign, which would itself be based around some enormous underground labyrinth (and which we today refer to as megadungeons).
I disagree with James’s assessment of post-1981 dungeons as a sideshow to the rest of the campaign in the Gygaxian conception; they’re certainly not the exclusive province of the game any more, but I think “sideshow” is too strong a word. But there is most definitely a shift towards what I refer to as “social encounters” as opposed to combat.
Back in Dragon #65 (published in 1982), Gygax first floated the concept of mystics, mountebanks, savants, and jesters. The specific features of these proposed classes is most definitely aimed at social encounters (especially the mountebank and the jester). They specialize “in deception, sleight of hand, persuasion, and a bit of illusion” (mountebank) and “influence many creatures toward kindliness, humor, forgetfulness, thoughtful consideration, irritation, anger, or even rage” (jester).
These, naturally, are at the core of the Adventures Dark and Deep™ game, and I think it points out a subtle point about the game as a whole; it is geared to accept this sort of play, where the ability to interact with a guardsman or an inkeeper is, if not the center point of a major section of the rules (like combat), is not left entirely to the role-playing and improvisational skills of the GM and player.
This is not to say, of course, that ADD (or, I would posit, Gygax’s own game during the period) goes overboard on rules to determine how such interactions should go, but there are at least guidelines consistent with the other rules.
I think this goes to a principle that was held from the earliest days of the game in Gygax’s campaign; that the idea was that getting treasure was much more important than killing monsters, and that if the treasure could be gotten by tricking the monsters and thus avoiding possible character death, so much the better. The idea that orcs could be “deceived” or “incited towards kindliness… or rage” feeds directly into that principle. Gygax’s latter-day series of articles in Dragon, sub-titled “All That I Need To Know I Learned From D&D”, exemplify this approach over and over again.
So I’m not so sure the addition of rules dealing with social encounters was necessarily a shift away from dungeons so much as it was a reaction to the way the players in the original Greyhawk campaign were playing in those dungeons. They were trying to be slick and tricksy, and the rules were gradually moving to reflect that sort of play, allowing them to be adjudicated with at least some modicum of regularity, rather than relying solely on the improv skills of those involved. I don’t personally see anything wrong or “bloaty” about that, and indeed I think the inclusion of such guidelines in the Adventures Dark and Deep game gives it a bit of depth that the original 1E may have lacked.
Of course, everybody has their own take on what is or isn’t a “good or needed rule”, and nobody is going to agree on such things all the time. Heck, I like weapons vs. armor class, and loathe psionics. Vive la différence!