I want Star Guardian, not because I actually want any more skins (I actually don't use skins from a full lineup like that unless a teammate is using one as well), but because they confirmed that the Star Guardian team mini figures would come back in the future. :P
If we're talking an actual skin theme, I'm definitely looking forward to K/DA. Pentakill is the only skinline I actually use on my own, so having another band is awesome! I'm just into music.
Now that you mention it, I'd like more Blood Moon skins. Hunt of the Blood Moon is my favorite RGM, and it'd be awesome if every champ you can pick had a BM skin.
If you want a more "actual" answer, I love it when champions have a skin that is all their own! Or ones that are linked to only a few relevant champions.
Elementalist Lux, Royal Guard Fiora, Popstar Ahri are good examples of the former.
The VS skins are a good example of the latter. Even though those ones are linked in lore, they feel especially made for each champion, as opposed to skins like PROJECT or Elderwood, which feel like they're meant to fit into the larger group instead of standing out.
So for me, it's a matter of what champions I want to get a skin in that regard. Top pick is Orianna getting an actual ballet-themed skin (I'd want Swan Lake, or Black Swan if you want to keep a darker aesthetic for her. Just hope she's still a pretty Victorian robot). Of course, she's getting a skin very soon.
(Edit: Added spacing to make it easier to look at)
