#1 - Convert the rest of your cosmetics to the new armor kit system
#2 - Iconic skins available to everyone. Both Morninglord and Shadar-Kai have solid skins that I'm sad I can't wear outside those iconic lives.
#3 - SHINY plate armor. Armor along the lines of this: http://ddowiki.com/page/Item:Elfcraft_Plate_Armor, but polished
#4 - Don't be afraid of color. We already have tons of black and grayish armors. When I'm looking at cosmetic armors, and over half have "black" or "dark" and the few that have colors in the name are just mostly gray with a muted color... part of what makes Red and Green dragonscale armor so pretty is the bold colors.
Direct Suggestions:
Enameled Armors: Take the Green Dragonscale armor and work out the dragon faces. From that, create an "Enameled Armor" cosmetic skin set. A color spectrum matching hair dyes would be awesome, but beyond the 5 existing dragon scale colors, do outside the spectrum already covered in game. Pink, purple, orange, gold, etc. If it is possible, a white pearlescent armor that changed colors at different angles... but that's getting a little too far fetched.
Just a Ninja Mask: I know a ninja mask exists, but it's a full headpiece. Just a mask that covered nose and mouth while leaving your hair style would be a good option.