I like
My problem with this (as with most quests) is how I make it fun. How do I make the quest to bring water and flour to the baker different to the quest to bring iron and coal to the blacksmith? Essentially they both come down to just walking to the item and bringing it.
There are tricks, such as making you go out into combat areas and explore/fight until you find the right things. Or making you solve a puzzle, buy the item, etc.
Ideally, the best trick would be to make you interact with other players. Perhaps you can just walk down and collect the flour from the mill, but on the way there will be bandits to fight, you'll need a noble to grant you passage, and a merchant to buy the flour. The quest itself, then, doesn't have to be so challenging, but finding the right collection of skills would be.
I've written up (but not implemented) a way of using quests to control the outcome of a war in the PCs home city. Politically, there are four noble houses (populated by players characters), with one ruling the city, and the others serving as ambassadors of sorts (more like vultures, circling, to take the city) - the problem is, none of the other three can take the city, it would throw the game out of alignment too much. The players know this, so it doesn't really lead to frustration, but wouldn't it be really cool if they were able to?
So, in my musings, I'm imagining that one of those houses decides to invade. NPC soldiers from their house start turning up outside the city. At first, just as random NPCs that you can bump into, but later they'd start attacking anyone not wearing their house's cloak, and quests to fight them would start appearing. New quests would also appear for PCs supporting the invaders, quests like "Sneak into the map room and steal the battle plans" - after either a short amount of time has passed, or a set number of those quests have been completed, the system would look at how many of each type were completed, and decide if the invasion continues, or withdraws. If it continues, next they might lay siege to the city itself, blockade the harbor, and so on. Quests to sneak messages out of the city, or quests to lower rope ladders for the invaders would appear. As the invasion continues, "basic services" of the city would vanish, but the invaders would gain new abilities. If the invasion is going well, invading soldiers would patrol the streets, protecting the PCs from their house, and attacking any "known loyalists" - specific quests like "capture the jail" would also appear.
Because of the loss of services (when the jail is captured, criminals can no longer be imprisoned, for example...) there is incentive for the players to muster a defence. Because of the soldiers targeting loyalists, there is incentive for players to avoid taking a side (or to help in ways other than drawing a sword... hopefully that would encourage a social underground movement) - and we would, of course, need incentives for the members of the invading political house, to give them a reason to want to organize an invasion. Ideally, this would be self-regulating. Players love to be the hero, and it gives the chance for the city to band together against a threat, while still having a non-coded social element that should create unique roleplay each time.
By having enough successful players follow the "right quests" they can put things right again, but it'd be up to player actions, if they side with the invaders, the game would be able to continue, with a new group in charge, and a loss of services to the city.
Individuals would be able to get to do the once-off events of invading or defending a city (setting dynamite before the city gates... fighting along ramparts)
To leave the game playable for the loyalists, there would always be somewhere to retreat to. The city is built, ultimately, around the original fortress of the (currently) ruling house, so as the invaders take more and more of the city, the loyalists would retreat until they end up in the castle. We'd then stop giving quests allowing more of the city to be lost, so the loyalists have somewhere they can be until they (if they ever do) take back the rest.
I guess why I'm rambling about this is because it's a setup that would have very simple quests ("go here" "fight that") but would hopefully lead to a much more fun story, and the decisions ("Do I really want to take a side" "I'm on the invaders side, but my friend is a loyalist...") should be where the real fun is.