I think most quest-writing is bogged down because it has to emerge from something or someone explicit. Remove that crutch and it becomes easier in my mind to write more unique and better "quests."
Oeolycus you stop reading my brain! The mod I would like to make, this has been one of my basic design principles.
Characters and locations in the world have their own stories, motivations, and activities... start there, and then build the game by constructing those stories and introducing some interaction elements. Granted you can't be perfect, at some point you can only put so many different reactions and setups into the game world before you run out of time or ability, but at least starting from stories independent of gameplay you'll be more likely to provide a richer set of options.
So an example would be, if I make a town you can infiltrate, I don't design it from the standpoint of: 'well what barriers am I going to put in the way of the player so they can get into the town', I start from a story of what the town is, who is in it, and how they would defend the town.
Then I create weaknesses, again based on the story, such as a guard who likes to sleep through his shift, a backdoor with a key, some other character in the world who wants to help you get in, etc. The end result is a harder game, since the town is not going to hit you in the face with how to get into it, but once you do get in there you feel like you have accomplished something because you managed to find some strategy to get through.
However it is hard to say whether that sort of design sells. Its clear that you can make lots of money with good scenery and fundamental mob grinding play... so like many things the simplest incentive dominates.