what we have right now is usable and we have more important stuff like class systems and weapon tuning to focus on right now but i would love to see maybe next year an overhaul to the shaders and cosmetic system...
cycling shaders 1 shader = 8 looks, mixing shaders together making your own custom shaders and making shaders cleaner/easier to use...
armor being saved into a transmog system for use on all classes i could put my titan ornaments on my hunter and the versus is true even ornamenting exotics to apply to legendary items note this dosent include weapons only armor...
speaking of weapons being able to apply shaders and mods to exotic weapons would be nice.