Thanks for the tip Nostrus.
Another point I wanted to make about UO that could translate here is world ecology. UO never was able to pull this off, mostly due to the limiting technology available at the time, but it was a desire of Richard Garriott to include it.
Basically you could have a situation like so:
A dragon hunts and eats deer in a forest to the north.
A local lord in the village wants to upgrade his local militia from leather to studded leather armor, so he commissions people to bring the village masses of deer hides.
Once the deer stock is depleted in the northern forest, the dragon starts feeding on livestock further south near the village.
Now that the dragon is terrorizing the village, the local lord hires adventurers to take out the dragon.
Once the dragon is killed and its cave/treasure discovered and looted, a wandering hill giant family finds the abandoned cave and moves it.
The giants hunt the re-stocked deer population in the northern forest....
Anyway, you get where I am going with my simple example. A dynamic world with and active ecology. The world itself would create quests and adventures.