@Riot - Karma and Particles
With this new Conquerer eSports skin for Karma, I noticed her particles have changed color, and nothing more to it. It's simple, and it looks good. However, Karma has a disturbing lack of particle effect changes across all of her skins, with only her two newest skins with different particles. Now I'm not an artist, but something as simple as giving Sun Goddess a yellow/gold filter to her particles doesn't seem difficult to do, and would at least give the skin something to set it apart from the base skin.
You've recently given new particle effect colors to lesser skins in Galio and Warwick's reworks, so going back on someone you've completed, like Karma, and doing the same thing would go a long way towards making her skins a lot more unique. I can't imagine it would even take that much effort in behalf of the design team to simply change the colors, so maybe just have it as a side project similar to what was done to Dragon Tamer Lulu's textures and Lux's new VO?