Age of Conan has been criticized for lacking costume diversity. It's not quite Age of Strikingly Similar If Slightly Recolored Leather, but it's close. The huge revamp to the crafting system that was recently announced will do a lot to fix this, adding new crafting recipes for armor sets including the Cultural Armor sets.
Massively had initially thought that the 'cultures' mentioned would be the three in the game currently - Aquilonian, Cimmerian and Stygian - but a recent feature on the new sets has added Acheronian to the list. It's accompanied by a lengthy piece of background text concerning niello, a substance that does exist in the real world, and will presumably appear in Age of Conan as a crafting material.