Quest systems

Reading this i realize that there are so much way to improve existings type of quest system in games.
Soldak do a great job with Depths of Peril, building a new type of game. A mix between a hack&slack, a rpg and a city-simulator: if you can read italian, can found on Maschera Riposta a exaustive review.
By the way, the problem is: how we can build news, randomized games, with deep storyline and decent quest system?
Here some ideas about quest:

- always important: never simply go to kill a cow. Keep the mood of the game is the first point. If player is a hero and want to become THE hero, must be do something that no-one (no one!) could do, start from beginning,
- never without consequenses: killing a guild-master or a goblin.. always a consequences; one immediatly (XP, kill a threat), one mid-term (affect relationship with victim faction and relations/equilibrium between factions), one long term (change story end, or some key-quest-element of the story). Killing is an example: all the quest must be done without killing. Let player decide what he want to do, and let him/her pay for it!
- always help player: no vague descriptions, no some "random text". Help player, if he wants to be helped! Map, minimap, descriptions, clear and shot term (for example: quest system in warcraft3). But let player immerse into game world without force him/her to read everything! If player quit from the game for some time, help him to enter in zero-time into game again!
- always see the progress: quest progression can't be something static.. If player decide to complete a quest, something else cannot be done. Use this against player. Let him/here decide, use the graph and some key-quest to determinate what player gonna be done into future. Show to player when he fail and when he win: player put his/her time into game, you must feel him this!
- random: use randomness to keep attention to player. Random not-important npc, monsters. Keep some key element fixed, but change. Diablo docet! Use random into quest creation (and into subquest step) and reward system, level creation (see the beautiful Spelunky) and so on,

and into end: let be the quest fun! Player wants fun, always fun, every player into world!