Guild Wars 2: Skin Collection and Vanity systems:
Get a weapon, lets say, Baldur Spear. When the spear gets into your possession, you get the skin entry in your vanity window to be used whenever you want, even if you don`t possess the item anymore. This would solve the inventory issue of this game in one shot. Also its dye system is just so amazing i don`t know where to begin, not only the number of colors is just vastly superior, but how you can dye up to 4 diferent parts of the same armor, from the leather straps to the metal plates to the small spikes diferently just... Just orgasmic. Imagine that level of customization in FFXIV.