I feel like the game could really be enhanced by switching Quests to a more standard NPC model. (NPC = Non-player character). In Glitch, I actually find it really annoying that the talking rock keeps popping up random quests at random times that I usually don't really care about.
At the same time, Quests are often the best/easiest way to get Currents & XP, so I end up doing them even though I don't really care.
By adding locations with NPCs, then there could be an ongoing dialog between myself and the NPC, that would ideally focus the quests in a direction that I want to go. For example, how about if there's a Bakery where only "baked" goods are sold. You could talk to the Baker to buy stuff, but then the baker could also give you quests that would focus your advancement in cooking/baking-related skills.
This idea is pretty standard in game design (and maybe that's why you've avoided it?) but I think it would really enhance the gameplay. Better yet, if actual players could "become" a Baker and sell items & give out XP to lower ranked characters for doing quests, that would be even more super awesome.
There are enough skill tracks that this could be generalized out to many, many different professions. Baker, miner, chemist, butcher, fruit vendor, vegetable vendor, machinist, etc. the list goes on and on.