The central problem: In what ways do you think D&D would change if it was designed to make the central challenge the dungeon (or the Adventure, or the Story, or whatever) instead of the encounter? What kind of rules might emerge?
Some dungeon-centric impacts/thoughts, in terms of how a dungeon or megadungeon acts as an active or a passive "threat" in the game:
- passively, the dungeon level may be
difficult to map, or its environs may be inimical to PCs (too hot/cold, no light, only stale air, non-euclidean, etc., etc.); the level might feature a lot of teleporters or secret doors, or it may be a vertically-aligned level vs. a horizontally-flowing one, or it may be an area of evil where turning is more difficult or where all undead regenerate or where non-evil magic is weaker; it may be a higher-level challenge, and therefore inherently more dangerous regardless of other factors like those above (or, the factors above may be more exacerbated in a more-difficult level: instead of the level's heat simply causing a point of damage a turn, it may be in an active volcano with poisonous gasses or pyroclastic flows running through the corridors at random....); and dungeon dressing should abound, to liven up otherwise drab corridors with something interesting! so, I see a lot of options in terms of how the "background noise" or the "baseline givens" of a dungeon can drastically alter the playing field for its explorers
- on the active side of things, the dungeon may be a very dynamic environment: the level design itself may shift and change due to shifting walls, moving rooms, falling blocks, and such; the use of teleporters is one thing, but dropping PCs into tesseracts or non-euclidean geometries is quite another; or, it may have intelligent inhabitants who reset traps, repair damage, excavate and build new areas, blockade old ones; or some of the inhabitants may be at war (literally, a la Leiber's "Lords of Quarmall"), perhaps; and there's always the possibility that the dungeon (or parts of it) are living, breathing (ingesting!) creatures, too (a la Moorcock's Agak and Gagak from Elric/Corum/Quest for Tanelorn, or from Leiber's "Jewels in the Forest"); or the dungeon may have a caretaker (Zagig/Zagyg, Halaster, etc.) who sticks his nose into things from time to time; my first "From Kuroth's Quill" column in Knockspell #1 featured the concept of
variable stairs (and other dungeon features), to provide just this kind of more active-engagement with mapping and with the features of a dungeon
In a dungeon-based game, I see choosing Door A or Door B being more key than choosing to be a dwarf fighter or a gnome wizard. If Door A leads to fabulous treasure, and Door B leads to a deathtrap, choosing Door B is probably the wrong choice, but being a fighter or a wizard shouldn't matter either way. If you're a defender, you might have a different way of dealing with the deathtrap, but ultimately, you still made the wrong choice in play (and now your party is closer to being killed before the dungeon is "beaten").
The dungeon should absolutely feature the element of random luck, but choices should matter, somewhere along the line too: the death trap may only target magic-users vs. fighters, or it may only target Neutrals vs. Lawfuls or Chaotics. Not all traps/features/etc. need to be tied to character creation choices, but there should always be reasons to reward or challenge all PC classes, races, alignments, etc. in the game---otherwise everyone would always play the same class.
what matters is the player's choice during play, not what tools you bring to the show. Your preparation only goes so far.
I think that goes a bit too far: PCs are different for a reason, and each brings different resources and abilities to the table for the player to leverage as part of the in-game choices they make from their options palette. I.e., elves detect secret doors well, and dwarves are good for finding depth and moving walls and such. Also: being prepared in the dungeon can mean many different things in different groups, whether that's having multiple mappers in case one is kidnapped or fails his fireball save vs. doing military "mission" style exploration (reconnaissance then attack the weak points or entering the dungeon to tackle specific objectives) vs. just carrying an extra week of food and 200' of rope.
I think making The Dungeon the central focus of an adventure can be accomplished by design. It should not be uncommon for Dungeons (and natural underground caves/formations as well) to be a hazard unto themselves. For example, various traps and hazards can be more memorable than the monster encounters if setup carefully.
Agreed completely.
Two words: Resource Management.
If you want to make the dungeon the basic unit of play, you must have resources that are used/managed within the context of that unit of play.
And that's interesting on a number of levels:
- time management: searching for secret doors or traps, listening for noise, and searching every inch of a room all take quite awhile, which means more wandering monsters will be met; AD&D is still set up on the round/turn, though, so I'm not sure how that might change when thinking of the dungeon as a whole, or as a "length of dungeon" time unit (it could apply to some spells/powers/skills/etc. being usable just once per adventure vs. 1/day, etc.)
- encumbrance: everyone hates it, but if PCs are limited in their capacity to carry big things around, it makes them choosy in what treasure they scoop up vs. what they use to distract monsters while running away vs. what they leave on the table/in the chest/on the floor, etc. (jewelry over gems over pp over gp, etc.)
- a well-balanced party in terms of races and classes and spell selections and equipment types, etc. allows the PCs more versatility to deal with various types of threats in the dungeon, including the loss of PCs too (so having redundancy built into the PC group is quite desirable)
Some of my thoughts above are definitely considering the idea of a mega-dungeon vs. a single dungeon level/adventure, with the distinction (in my head anyway) that you can't really beat/win a mega-dungeon vs. a standard dungeon (well, Robilar did, but that was way back at the beginning of the history of the game

).