Like hold a contest to see which one sticks then design a skin around the idea's presented. So many great concepts and skin ideas have been done already, it's a shame we rarely see any come to life after all these years.
Ice Birb33 votesofc star guardian urgot is going to win the first contest
RainbowIcee4 votesand we would all love it! though i personally vote for lollipop urgod.
Mhihnj3 voteshuman thresh/sion/kalista etc.
Wrathof30010 votesI nominate the Gatekeeper 
as the first one!
Edit: should Riot go thru with this idea which I think they should 100% discuss at Hq.
Mattwiki1 votesThe only Gatekeeper skin worthy enough for our wallets is 
, in memory of Fabbbyyy the gatekeeper.
MonkeyMadness7 votesWait. Are you insinuating that Riot should both listen to your request for a cool event AND ALSO adapt player-created content to add to the game? Wow, and I thought I dream big...
An Undead brat3 votes[deleted]
Velzard of Koz1 votesStreet Cleaner Yorick
50ShadesOfÀDC3 votesPizza Delivery Sivir would be best for that.
Litzkrieg2 votesWhen you equip the skin, her R is renamed to "30 minutes or less".
Leetri2 votesI can almost guarantee that it's not a possibility simply because of legality issues if we're talking actual concepts. The only way around it would be to hire the artist as a freelancer and even then it would have to be a new concept they haven't already done outside of Riot. I doubt Riot is willing to hire everyone who enters the contest, even if only for a month. If we're talking just ideas, then we're still gonna run into the issue of this being the internet. You can 100% be sure that the top results would be like "Gushing Granny Annie", "Hitler Did Nothing Wrong Udyr" and "Robot McRobotface Blitzcrank". That means Riot would have to limit what our options are, and then what's the point? Riot already knows what sells the most, so why would they ask us when our wallets have already spoken. You might say Star Guardian Urgot, but I'm willing to bet 99% of the playerbase don't want an Urgot skin because they don't play Urgot. And if they do, they might not want Star Guardian Urgot, they might want Dreadnova or Elderwood Urgot. All this poll is gonna lead to is champions like Riven, Yasuo and Ahri getting more skins because they're the most popular and people want more skins.
It's a really good idea in theory, but being the pessimist I am I can say it's most likely way more trouble and work than what it's worth for Riot.
Nickfer25101 votesThis should already be a given. The Concepts and Creations Boards by themselves have really creative ideas for skins; it is surprising Riot ignores almost all of them (if not all).
Wrathof3001 votesI don't really blame them, because despite the rules Riot have set out about those boards, there are people that will still be like "GG WP Riot, selling fan's ideas and not giving credit".
RainbowIcee1 votesi'm guessing because some of the concept might be close to already existing ones... but then there's yellow jacket shen.. and you know.. talon as a whole.
OnanThaMan1 votesIn theory this would be awesome, as well help heal the rift that has formed between Riot and the community. Have a waiver or something when they submit, that says you are fine with Riot taking the idea and making a skin off of it and profiting without any monetary compensation. So you know, someone couldn't try and screw them over, and sue them.
DariusDemiurge1 votesHeavenly Morgana. :3c disregard she already is heavenly but you know what I mean.
Sexy Jack Rabbit1 votesAnd have a repeat of this tragedy? https://image.prntscr.com/image/gcFsP4bBRsir-D46Pqhkrw.png
I'd rather Riot stick to making fan concepts a reality, as opposed to a system put in place for these kind of skins.
kda akali1 votesHi-Rez just did it wrong honestly
https://i.gyazo.com/5a549a58c211dabaeef1804025a705ae.png
The original concept for Angelic Awilix is stunning. Hi-Rez went too far away from the original design and made the skin look more like a bland cosplay of the original concept.
Sexy Jack Rabbit1 votesPretty much my point. I'd really rather Riot continue their current method of taking fan concepts and turning them into similar skins. But not directly recreating them. Ice Drake Shyvana started out as White Fire or something. Riot just took some ideas with it and changed some stuff.
If we got this system that turned fan skins concepts into in-games skins there would no undoubtedly be an outrage when Riot would have to change aspects of the skins to make them work in game, or when they cut corners to make the skin meet a release date.
Xenos von Faneli1 votesThis is a fantastic idea tbh, thought I do feel it runs the risk of playing favorites and just being one big Yasuo/Ahri/etc skin popularity contest.
crzymdscntst1 votesIsn't Beekeeper Singed a skin that's been bouncing around the forums for a long while now?
(As in, given the right circumstances and qualifications, maybe this could actually be a thing?)
