Specific to 1e D&D this makes sense, though I take issue with describing it as reduced to no more than "a puzzle-solving, maze-solving exercise". More broadly and less system-specific, the game is in part about exploring and learning about the setting through the eyes of your PC, whether that setting is provided by the DM or by something pre-published e.g. Greyhawk, Golarion, whatever. This exploration largely assumes a setting that is more or less in place waiting to be explored.
'classic' D&D (by which I mean essentially TSR D&D) follows an arc of development. The earliest conception of the game is of a vast dungeon, filled with treasure and monsters, which the PCs explore systematically. It may, or may not in some cases, be associated with a 'town' where the PCs can recruit henchmen, heal, buy and sell things, etc.
The next stage of evolution was to include a 'wilderness' which follows a similar formula (entirely generated by the GM and discovered by the players through action resolution, with its characteristics, the facts of the game world, acting as constrains). This wilderness exploration stage starts to break down the paradigm, because the dungeon puts hard constraints on things, you can only travel by the prescribed routes, etc. but the wilderness has far fewer such constraints.
Finally high level play created even greater issues by further breaking down the constraints and thus making it hard for the GM to anticipate the course of action. It also involved things like 'freeholds' and such, which are MUCH more abstract and rely on highly subjective GM judgments.
As players demanded more dramatic elements in play the game evolved in conception ultimately to 2nd Edition AD&D where the game EXPLICITLY states that the objective is to create interesting stories involving the PC's heroic exploits.
The point being: what [MENTION=42582]pemerton[/MENTION] describes is a pretty accurate summary of the essence of the Ur of D&D, its primordial mode of play. I can attest to the accuracy of this description since I both played and DMed in this period, the mid-70's.
This is the contention with which I disagree: I don't at all think "most" contemporary play has moved far from its classic foundation at all, but has rather added the bits about interesting characters and story on to what was already there.
On the contrary, from the publication of the module A1, which was, IMHO, the first 'story based' adventure to be published (someone will probably find antecedents, but it isn't that important) the game left the original paradigm behind in the sense that the narrative was now ABOUT the characters and their dramatic needs and evolution. It was CERTAINLY far less constrained than previous play. Even the 'D' modules don't really have the degree of reliance on plot and character motive that A1 has. D3 is a pretty big 'sandbox', but its still really a pure exploratory exercise, just writ large.
So, I would say that A1 marks the 'death of the dungeon maze' as the principle paradigm. I can attest, again by having been there, that this was a conclusion drawn AT THE TIME by both players and reviewers of this module and its successors.
While I agree that play methods have NOT in a lot of cases evolved too much, I will address how this is in tension with actual play practice below.
It puts some more work on to the DM, but it's not impractical in the least. The players just have to realize that they're quite realistically almost never going to have all the information they need, and that now and then this lack of information (or flat-out inaccuracy of information) is going to mess them up. On a broader scale, the players have to accept that the GM is going to be keeping secrets from them only on a bigger scale than simple dungeon-crawl play would expec, and that the GM is going to be informed by these secrets when determining the results of PC actions.
The PCs (and players at the table) won't always know why some action or other resolved the way it did...just like real life, that way...and this is not a problem unless the players at that table feel they have some sort of right or entitlement to know everything about anything that affects their PCs including things their PCs have no in-game way of knowing - at which point those players can find another table, 'cause they ain't playing at mine.
Yes, and these factors are in tension with, and undermine, exactly what you contend is 'easy'. In fact it isn't easy at all! 2e D&D is so infamously incoherent in the alignment of its declared narrative agenda and its GM-centered and often procedural mechanics that it hardly even bears comment! The only way to achieve the sort of narrative story arcs imagined is Illusionism and GM force, and the stories themselves must largely stem from the GM's imagination. You can read my previous post responding to Maxperson on the impossibility of unsignalled agendas leading to the desires story arcs and how this makes his proposed method of play literally a negative-image of Story Now.
Yes - exploration of the game-world or setting in which the PCs find themselves. It's one of the three pillars of play that have always been there but weren't clearly defined as such until 5e D&D came along.
In effect, as this discussion has gone on, it's become evident that the OP is asking whether this pillar is worth keeping.
Lanefan
Needless to say, I have little use for the maunderings of Mike Mearls. I think his idea of 'pillars of play' is unhelpful at the very least, and is at best an analysis of one facet of one specific technique of RPG play, which he seems to imagine is somehow all-encompassing. At the very least he seems to imagine that it is all he need ever address in terms of catering to his specific audience. This is part of the reason I have analyzed 5e as the 'tombstone' of D&D. It envisages no further horizon, and no ambition for any wider play experience, or any desire to explore beyond the boundaries of existing D&D lore, play techniques, rule formulations, etc.
So, speaking for myself and not the OP, I don't even consider the whole question of 'pillars' to be interesting. I've reformulated by own flavor of 'D&D' upon an entirely different set of precepts. The idea of pillars and some sort of 'balance between them' is irrelevant within my conception. That doesn't make exploration an impossible agenda, it just puts it at the level of agenda, and not of a 'mechanical space' within the game's rules construct. Put it this way, I would say that if a player chooses to make character build choices and narrative choices which focus on abilities which relate to exploration, then Story Now concerns dictate that the GM in a HoML game would present exploratory challenges.
I would say that, dramatically, exploration is generally more an element of framing than it is a direct response to character development. In other words a character, dramatically, is unlikely to have an agenda that is purely 'explore for the sake of exploration'. If I was presented with a character which the player had drawn up like this, the first thing I would do is challenge them to explore the MOTIVE for exploration, because exploration is an ACTIVITY, not a belief or end goal.
Lets imagine, a player might respond that he is a worshipper of Ioun, and holds exploration to be an element of devotion to his patron. So now the character's core belief has been refined to a dedication to Ioun, and that probably has some motivational story attached to it. The exploration element isn't being denied, it is described as an interest and avocation of the character. It just isn't what we would generally leverage. A story would take place WHILE exploring. The story might test the character's devotion to Ioun, maybe by making exploration a costly activity in some way (IE loss of lives, wealth expended, necessity to make morally fraught choices, etc.). So I can frame a scene as "while exploring XYZ, your brother-in-law falls in a pit and perishes, what about that?" (I'm extrapolating the outcome of the action here, as well as the initial framing). How does the character break the news to his sister? Does he consider this price to be worth the service to Ioun which it represents? Just how far will he go? Will he sacrifice 10 lives to cross the mountains? 20? 100? How will the folks back home treat that? Will he be able to return and face them?