D&D needs adventures!
Okay, I finally have a chance to jump into the discussion again. Cannonball!!
Celebrim, your five points definitely represent very key elements of successful adventures (Nikolai's addition falls mostly into your 5th point, I believe, but it too is important). With regard to your first and second points, I think we agree. Moreover, a good story should generally lead to the creation and development of those aspects of an adventure that involve "evocative situations" -- thus encouraging the players to care about what happens. As I mentioned, a good, engaging story lies at the core of any successful adventure.
With regard to originality (which also ties to Nikolai's point), the very notion of a game designer as opposed to the regular DM sort of inherently suggests that the designer should and even must come up with stories, ideas, and uses of the rules in a way that captures the attention and imagination of a DM. Good NPCs, for instance, more truly function as elements of the story: if they have clear and intriguing motivations and distinct personalities, their role in the story should be memorable. Then again, much of an NPC's significance to the players relies upon the DM -- i.e., how he plays the NPC in the game. A designer can create the most intriguing NPC ever, but that could mean little if the DM does not take the material and do something interesting with it.
Still, after a while, with so many DMs out there and several of them having DMed for quite some time, ensuring that a particular adventure presents a
completely new twist, trick, technique not yet seen or done before becomes difficult . . . if not unrealistic. This point also addresses Nikolai's regarding standard vs. unusual monsters: asking that an adventure contain encounters with only unusual or extraordinary monsters is somewhat unrealistic, partly because the "standard" forms go toward saving the DM time in many respects and partly because unusual monsters should not be included simply for the sake of doing so in order to show off one's originality. Unusual or extraordinary monsters work best in service of the story. Granted, the d20 rules most certainly provide designers with a wealth of tools -- if not the incentive -- to tweak standard monsters. Such tweaking, however, must have a purpose. Tweaking for the sake of tweaking merely demonstrates one's agility with the game mechanics, not one's prowess at crafting a good adventure.
As for maps, well, I agree and disagree. I think that you overstate the case, Celebrim (i.e., asking for professional architectural training in your cartographers), but that you also make a valid point. Maps can definitely also capture a DM's imagination, but to make them the single most important element of an adventure product quite quickly focusses upon a aspect of an adventure that bears little relation to story and originality. Admittedly, the maps should be good if not exceptional; poorly crafted maps do hinder an adventure product's overall quality. Maps, however, are a primarily physical and functional element of adventures. As well, we should not forget that some of the most successful modules included pretty average or even amateurish maps (
Temple of Elemental Evil, anyone?

) -- in the distant past and more recently.
Celebrim wrote:
Mark my words. We are hitting crunchy bit saturation. Sooner or latter everyone is going to have more rule books than they can use, and the only people still making money are going to be the ones that have settings and stories that excite people and attract a fan following.
With this sentiment I agree completely, and this is why I think that adventures could make something of a comeback over the next little while. Adventure designers still face the nightmare of "crunchy bit saturation," but, as you suggest, if they can give us exciting stories, then perhaps all of that "crunch" will get put to good use.

I'm also going to bet that we'll see adventures incorporating more and more OGC, which of course offers designers a truly vast field of opportunities for flexing their originality. FDP will be using OGC in its adventures this year; I have edited adventures from Necromancer Games that include OGC.
As well, I think that adventure designers likely now hold more awareness than ever of making their adventures as "portable" and/or "adaptable" as possible (another mark of quality and originality, perhaps). Such portability relates a bit to jester47's notion of focussing upon locations, though the key remains a good, engaging story. For instance, one of the initial design goals behind FDP's
Gates of Oblivion was to give the adventure a kind of "dual" utility: on the one hand, that kidnapping plot wrapped up in a planar adventure I mentioned in my previous post; on the other hand, providing the DM with several very interesting locations and encounters that could easily be pulled out of the adventure and used as the DM sees fit. It's the balancing act between offering a great story in an interesting setting and not making an adventure so tied to a particular setting that it cannot easily be adapted by a DM to her own campaign. If that makes any sense . . . .
In the end, one way of looking at adventures might be to see them as real goldmines of ideas and inspiration, even if the particular story or intended character levels do not exactly match a DM's group and/or playing style. They are brimming with locations, NPCs, situations, plotlines, crunchy bits, and so forth. Of course, the best adventures will excite DMs to run them (almost) as is.
Perhaps, though, johnsemlak makes the best point. Adventures, when you really think about D&D, form one of the most crucial parts of playing the game. There is no game without an adventure. You can still game without all the class and splatbooks at the table. You cannot game without a story, a goal, a quest. Published adventures, then, fulfill a basic need of the game; the good and exceptional published adventures enhance the game immeasurably.
Right, again that's enough out of me. I think my dog will have a hernia or something if we don't get out to the park RIGHT AWAY.
Take care,
Mike