I can't beleive nobody has mentioned yet the crafting system in Baldur's Gate 2 SoA... that was AWESOME!
Does anyone remember the Crom Faeyr or the Vorpal Sword? The most powerful weapons in the whole game, scattered into multiple pieces in the whole gameworld, having to hunt down each unique component one by one and hiring a master blacksmith for extreme amounts of gold to put it back together in a couple of days (or weeks???, that part is a little foggy in my memory).
Something like that would be perfect, with each craftable item truly uniqe, perhaps supported by consumable crafting and minor enchantments for regular equipment.
Also, the pantaloons, anyone? Wicked.