The way I've got it imagined is that each item gets it's own page. The page should contain the contextual item descriptions, the item effects, how much the item sells for to NPCs, where to buy the item (if possible), what monsters drop the item, what quests use the item (or, more generally, what the item is typically used for, crafting, etc).
All of the item pages are linked into a tree of categories which essentially act as filters.
Category:Items should act as the "master index" of all items. It should additionally contain subcategories like
Category:Weapons and
Category:Food which contain the appropriate item articles in addition to further subcategories (ie,
Category:Swords). This way, an easily browsable hierarchical structure can easily be maintained which contains all of the items.
Monsters are a little tricky, since there are only a few archetypes from which the rest derive. I think they have different drops though, so that alone warrents a separate page for each monster. The monster's pages should include a picture of the monster, a short description (it would be great if there were some kind of monster library in-game with nice tidbits of text on them, but that's a longshot), what items the monsters drop, what skills the monsters use, where the monsters can be found, how much exp they give, and potentially strategies to kill them.
The strategies part is a potential nightmare because it's highly opinion-based. It might be better to put that kind of information on the talk page and leave the article only for purely factual stuff.
I really haven't given much thought to quests, since bellynn was working on the part-time stuff (I guess he stopped bothering with it though?). My plan would be the same as always - an article for each quest, then divide into categories to create multiple hierarchical views of the article set. Some of the quests (ie, the random owl ones) are going to be kind of tricky, since there are multiple quests with the same name that can be acquired in different ways. We'll figure something out.
Eventually, the entire wiki should form a beautiful hierarchical tree, with the main page as the trunk, branching out from categories into articles, such that a user can easily locate any piece of information starting from the front page, and gradually narrowing down their search. Ultimately, this probably means a lot of "short" articles since gathering the raw information is really time consuming, but getting the overall structure down is key. Without structure, data is useless.