(stolen thread and comments from reddit)
Popular champions pay the bills.
Ornn, Xerath and Shaco skins do not pay the bills.
Without them consistently releasing skins for popular champions we wouldn't be getting things like Teamfight Tactics for free. LCS wouldn't be free either.
Despite that they still have in fact released several skins for unpopular champions this year.
Brand, Shaco, Anivia, Nunu, Leona, Ivern. They also gave skins to Jayce and Kat who aren't unpopular but hadn't received one in a long time.
I get that it sucks if you are somebody who mains a super low play rate champion but that's just how it works. If you were in their position would you rather release an Ezreal skin or an Ornn skin?
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Ppl are crying about prestige skins, while many of them asked for them, they asked for something expensive, to show support to Riot.
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Making skins for popular champions may also be due to artists. It's not like there's a huge line of people wanting to create Kassadin content. Most artists probably want to make things for champions that are popular (more exposure for their work) and their preference for things to design are probably along the lines of the general populace.
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The thing that bothers me about these skins is that they just suck.
They're so fucking ugly. Yasuo is actually Sewn Chaos Blitz/Mumu tier bad if not worse. It's one of the WORST skins Riot has put out in years. I'm honestly shocked it got past so many people at Riot who are paid to look at skins and think "this is okay". At least Sewn Chaos skins were creative and TRIED to take the champions in a unique direction.
They just slapped a pixel tornado onto Yasuo and called him Battle Boss. If I was a Yasuo main, I'd be pissed that he's getting a skin of such mediocrity. Kai'sa and Caitlyn are just a mash of colors with some voxel fx and a new VO filter.
Like I have no problem with stupid teenager jerkbait champs receiving skins frequently. It's always been that way. But these skins are just insulting to everyone.
↑ this is called opinion, often times, when players don't like something, they will go to first platform and whine, that's why there aren't many ppl that would say "I like it"
My opinion? Don't buy them? Keep on whining and you might get your Ornn skin for all 5 otps.
all need skins bad and as for 
their lunar skins are trash all they did with sej was throw on Chinese clothing and make Brissel a fat pig because it's the year of the pig worst skin on league but all these lunar skins where so well made 
