In Star Wars: Galaxies resources were rated on different aspects like Malleability, Conductivity, Toughness. I like that idea and think something similar is in order for this game.
However instead of stats being so random I think it suits a fantasy game better if different resources are different quality. Mithril may have some small variation from bar to bar but it is always lighter and stronger than Steel.
The presence of crafter resources that are better and rarer than more common resources provides a great opportunity for plot to be attached to them.
Let me give an example. The absolute best bows in the game are made of Ent-wood. Moreover any woodworker making an item out of Ent-wood gets a lot of exp. However any Woodcutter cutting down his fellow guardians of the forest actually loses exp.
So an unscupulous Woodworker persuades a naive young woodcutter to go with a group of adventurers Ent-hunting. The day after he turns the treants into planks (or next log-in) the Woodworker player receives a private cutscene pouring on with a trowel the tragedy for the woods of enticide and the cutscene is followed by a "You Have Lost Experience" message across the centre of his screen.
Then a window pops up.
Advanced Class Unlock: Druid
Become a druid? X Stay on as a woodcutter? X (check one box)
Now to further enhance this add in an ecology for rare creatures. Let's say there a 50 ents in the world at the start and too all intents and purposes they don't breed. Players will drive them to extinction creating several druids. One day the druids will log in to see a message and cut scene A Species Has Become Extinct. You Have Lost Experience.
Ents becoming extinct enables an obscure quest line to restore them once more to the world. The quest line will pit them against other players in some way, possibly they might have to get all those Ent bows back off master archer players and snap them. Oddly at this stage woodcutter players have an incentive to subtly help the druids - the best crafting material in the world for them will only become available again if the druids succeed.
Player character resources
Certain items and spells will require players as resources. For example the Dread Lord Ts'amanach can only be summoned by a Master Demonlogist who sacrifices seven elf players as part of the spell.
This naturally leads on to a consideration of more personal character details than players are used to providing. Characters should pick whether the avatar is a virgin on creation. Possibly that may change during play (although I'm thinking Gone With the Wind style curtains blowing in the bedroom window to suggest sex rather than actually making a pornographic game).
There may be a stat bonus for being a family member. +0.1% to hit or craft if a family member is within 50m. That means people have to create virtual family networks which allows evil magic involving people's firstborns or seventh son of a seventh son and so on.
I have quite a novel idea for durability: the Pigpen look
With a nod to the late great Charles M Schulz, the idea here is that all new crafted gear looks reasonably decent and as it loses durability it starts to acquire a muddy-brown pigpen look. Your sword won't fall apart if you don't maintain it it will just look crap. In addition the more fancy an item the lower its durability. A gold bikini with tassels and bells on it will acquire the pigpen look after a three day trek through the jungle.
This keeps an active market for player crafters without forcing adventurer players to loose exceptional gear.
All gear is player-crafted
Boars don't drop plate mail in this system. Creatures will provide crafting resources but like the real world stuff you use is generally made by other people.
Exceptions: anyone can pick up a stick and use it as a basic weapon. Wilderness-based players will be able to find shelter and work out how to carry water without needing player crafted items.