We can engrave our armor, paint it different colors, and add on color schemes and symbols.
But you know what we don't have, yet? Textures.
I propose that we should be able to change the "Texture" of our armors. Similar to the Base colors of Default, Dark, Red, Gold, White, and Black.
For example: Knight armors should have options like "Mirror finish", more or less shiny, and other things of that description. The various ways to treat metal. Samurai should have options like polished/varnished wood, hardened wood, shaved, and natural. Viking's leather should have options like "cracked" or hardened and other stuff. Cosmetic options.