I would love to see a mega-adventure along the lines of Dragon's Crown rather than Return to the Temple of Elemental Evil. Dragon's Crown was the stand-alone finale to a set of Dark Sun adventures (the only ties backwards were an NPC or two, one of which dies off-stage, and the included pregens), and featured an evil but well-meaning plot by an order of powerful psionicists to block all psionic use for a generation or two (because they thought psionics were misused). Anyway, this plot has the characters travel to the very edges of the campaign map and beyond, making quite a few stops along the way, and showcases many of the setting's features (savage halflings, thri-kreen tribes being driven mad by the thing that keeps others from using psionics, ancient fortresses, fragile alliances with sorcerer-kings, and so on).
Return to the Temple of Elemental Evil, on the other hand, is mainly a big honkin' dungeon crawl. It's a well-crafted dungeon crawl, but it's still "slog through the dungeon for five or ten character levels" - that gets pretty dull after a while. Dragon's Crown has its share of dungeoneering, but it's not the main focus of the thing, and there are pauses between the dungeons at least.
Return to the Temple of Elemental Evil, on the other hand, is mainly a big honkin' dungeon crawl. It's a well-crafted dungeon crawl, but it's still "slog through the dungeon for five or ten character levels" - that gets pretty dull after a while. Dragon's Crown has its share of dungeoneering, but it's not the main focus of the thing, and there are pauses between the dungeons at least.