looking at the current project skins, there is a difference in the old and new ones regarding brightness. maybe they're keeping their options open to having two full teams of project skins with light and dark colors.
light:
dark:
ones i'd like to see: 
F2 SiegZeon1 votesi would like it if riot made ahri a project skin <3
Toa Innodence1 votesthat could be interesting, but ahri has about 4 more skins than azir.
and graves doesn't have a cigar.
F2 SiegZeon1 votes[{quoted}](name=Toa Innodence,realm=NA,application-id=A8FQeEA8,discussion-id=q8hzEzWb,comment-id=00000000,timestamp=2015-08-21T19:36:20.822+0000)
that could be interesting, but ahri has about 4 more skins than azir.
and graves doesn't have a cigar.
i am a ahri lover <3 who do you main :D?
Toa Innodence1 voteshaven't found a main, but leona and diana are personal favorites at this time.
Bultz1 votesAs a Yasuo main it bugs me that their making more project skins. Our only unique skin, one of only two buyable skins, is now common place. Lame.
Toa Innodence1 votesCry more. Azir only has one other skin that isn't even "unique" by your definition.
Bultz1 votesWho cares about Azir? If you want more skins for him ask riot. Just be like riot i want pheonix Azir. Riot i want necromancer Azir. Ive payed against many Azir none of them had a skun. The less people buying it decreases his popularity rating meaning riot wont make more. yasuo is vastly more popular. Plus he needs a huge nerf. azir is op AF.
Toa Innodence1 votessounds like you solved your own saltiness about lack of yasuo unique skin: ask riot for more skins. it'll take them two years
in all likelihood.
Desiderium2 votesYasuo is one of my mains, and I'm extremely surprised why you would see this as a problem in any way whatsoever. I mean really, so what?
Toa Innodence1 votesMore the merrier in skin groups.