For me? I feel like Elderwood Lulu would be amazing or an ultimate skin. Her entire story is based around her being stolen by Pix and pulled away into a forest where she completely went crazy. And I could totally see her being absolutely overrun by the very forest!
What about you guys?
Arcade 
PROJECT
Astronaut
Warden
Pink 
i mean i already have dunkmaster darius so i cant really think of anything
Ronald Shacdonlad 
4 Seasons Rammus
His model changes depending where on the map he is. Each lane has a respective season, and throughout the game, as Rammus moves around, his model would change too.
Autumn (Mid) Q: A pumpkin, rolling around. A trail of leaves would be left in his wake as well. W: A leaf shield, like leaves being blown in the wind. E: Small animation of Rammus throwing leaves at the enemy, and a big cookie appearing around their head for a moment. Compare this to his regular E animation. R: A ring of leaves would be thrown up in the air, then slowly float down and fade out.
Summer (Top) Q: A beach ball, rolling around. A sand trail would be left, similar to Autumn. W: A coconut shell rotating around. E: Rammus spitting a small squirt of water, and then blue water-y waves echoing out. R: Sand being thrown up close to him, and water being thrown up further away from him. This should resemble a beach.
Winter (Base) Q: A large snowball rolling around. A similar trail of snow trailing behind. W: Shield of snow, like a snow globe, whirling around. E: Rammus throwing a small icicle at the enemy. Icy blue taunt particles. R: Snowflakes being thrown up in the air, and slowly fading out.
Spring (Bot) Q: A big dirt ball with patches of grass. Flowers could grow then fade out behind him. W: Flower petals, all colours, whirling around Rammus. E: Rammus throwing dirt. A large flower would echo out and fade away. R: Pink flower petals could be thrown up in the air, and slowly fade out.
i feel like a demon blade yasuo would be cool
my concept is that he slowly gets more absorbed by the demonblade over the course of leveling up
by level 18 his eyes are completely white, he has red scorched hair, and becomes overridden with power
also after he ults at lvl 18 his sword lights on fire for the armor pen
2 things for me. I main 
and so there is
A- 4 seasons zyra. This idea has been tossed around a bit but yeah.
and B- My idea was for Coral Reef
Her q and ult could be spiky coral and her seeds and plants and stuff could be like anemone's and other cool sea life.
A space-themed skin for 
.
Something less along the lines of Dark Star or Aurelion Sol's design but more like Cosmic Reaver Kassadin. For instance, imagine this theme: http://ddragon.leagueoflegends.com/cdn/img/champion/splash/Kassadin_5.jpg ...on Bard.
Project Brad.
Read my tale, I've described it at the end of chapter 1 :DD
KING KLED RIOT MAKE IT HAPPEN!
Don't really have a main but I would like a skin where you can choose for them to be more dark or light and they get model changes and VO changes mid game.
Like how in Infamous the good path look different from the evil path.
http://static.comicvine.com/uploads/original/11115/111156380/3987345-cole+vs+delsin.jpg
If I were to chose though I probably pick Shen
Dark http://whofedthischamp.com/images/uploads/958/Outcast-Shen-Fan-Art-full.jpg https://i.ytimg.com/vi/YJ61vv-ba0Q/maxresdefault.jpg
Something like this would be good for the dark side. His quote would be more cruel and he is more of and anti-hero who would kill to stop the bad people and the good side would be more merciful and have a more heavenly look with the mantle of decorum.
Since Shen is melee and he doesn't have much special effect I think it would be good if each form have different attack animations too. I mean Udyr have 4 different attack animation so why not.
The dark path would have particle similar to Zed because after killing zed in this alt-uni the shadow now possesses him as for the good path it would have more a holy light effect.
I don't know what would be a good name for this skin of this nature, any ideas?
Sweetheart 
Dragon Tamer
Prehistoric (Caveman with a club on a dino)
Mafia (Beatdown people with a baseball bat)
Special forces
Project
Senna 
With a real weapon
Some super bitchin talon skin where hes all cooler and stuff saying spooky ass shit
while infernal susan is nice i cant help but feel this idea to good to pass up
soul reaver nasus
passive: it makes a effect everytime he autos it looks almost like he is sucking there soul out. the more he life steals the more detailed/powerful the effect looks
Q: it makes a shriek that gets louder as he stacks. at some point can be heard globally. toggle for both teams. if he misses stack nothing really happens. if he stacks a special death animation of a soul being pulled into nasus happens. bigger for +6 stacks of course. similar to spirit gaurd udyrs unique death animations on minions W: chains wrap about the target pulling at there soul more chains appearing over time before finally breaking. E: blue fire. looks like whispy souls screaming without sound R: when nasus stands near enemies strands pull from there bodies to him as he drains there health for his ad.
Eye of Twilight 
Master of Shadows 
Ultimate Twin Bundle: Destinies Reversed!
Illaoi completely possessed by Nagakabouros(The Kraken God)
Straightjacket
He wouldn't just fight without a weapon, he'd fight without arms!
But in all seriousness, I would give any amount of money to see that skin.
Orgins of Mundo skin - we follow Mundo through his mad scientific journey. His appearance would change based on his level and how you leveled his skills.
I would personally love a skin detailing the story (or theory coughsennacough) of 
through the game.
like she would start out fully clothed, in her pre-shadow isles look, her quotes, animations, and model would change over the course of the game based on how many kills/cs she gets in addition to levels to show her changing into the sadistic smurf everyone loves to hate.
Undead Rat Twitch. Starts off the game as a newly killed rat. As the game progresses he would visually decay more and more before finally becoming a half decayed zombie specter rat. Q would convert his current state of decay into ghost form for the duration of the stealth and attack effects would be ghostly blue flames.
Arcade Brand looks promising. Also would like some kind of Zombie Brand, but with more deep green colors, and nature-related animation. And some kind of voiceover Galio has. Yeah, that would be cool.
Devourer of Worlds 
.
No initial change upon game start, same old catfish. Appearance changes after he eats something. E.G. eats allied Caitlyn, gets a purple skirt and a top hat. Eats enemy Darius, gets a wicked set of red-and-black armor. Eats Gromp, turns into Gromp.
Virus 
Matrix rain visuals, quotes that reference computer programming and bugs. When he procs his passive on a target their model glitches out briefly.
Time Lord Ekko/Zilean, Cyberman Viktor, Dalek Blitzcrank
-pai.
I'll leave this one to your imaginations.
Nekomata 
Give her cat ears and a cat tail and have her say cute stuff like "Nyah" or "Nyu"
:D
Super Galaxy Gangplank
Mecha 
I can just imagine as he goes into Mega Gnar, his parts shift and change. Instead of the gibberish, it could be like grinding gears, garbled messages or morse code.
They already have Mecha Zero 
, so I guess I'll say Harambe 
Arcade Ezreal. qB^)
well for 
its tied with Pool party Arcade and Project those skins could offer him so much and he has so much to offer those skin lines
We NEED A Mecha/Full Metal 
Blood Moon Evelynn or Warden Evelynn
Arcade Ahri is pretty close with new particles and the tails turning colors.
This sounds like a stupid idea but... Avatar Taliyah. Throws lava in fire state, Throws ice in water state, Throws tornados in air state, and Throws rocks in earth state. I feel like it would look cool.
Tbh Blood Lord Vladimir is probably the best thing they can make for Vladimir so I'll go with the champion that I have my second highest mastery in (although I haven't really played him since S5): Zed.
They should make a skin for Zed where he starts out as an innocent, albeit jealous and angsty, apprentice to Shen's father. Whenever he levels up Death Mark, he progressively slips a little further into darkness and he ends up looking demonic and perhaps a tad similar to Nocturne as he becomes completely consumed by the shadows.
Firestorm Illaoi...
cause shes champ 420.
I don't main any champs, as I sort of just play whatever I'm feeling(or whatever's needed) in the moment, but I already proposed the idea of a Lycanthrope 
skin where she sort of loses her sanity and refined fighting style as time progresses.
For her appearance, I was thinking her clothing could start out tattered with blood covering her armor whilst her body presents scratches, with her speech and quotes faltering and slowly becoming more feral/primitive with time, before she completely transforms into a full-fledged werewolf.
Ditching her weapon for razor sharp claws, her dash becoming a wild lunge, her parry becoming a stalking crouch just waiting for the opportune moment to lash out, bladework becoming a savage series of gouges, while grand challenge becomes crescent moons and causing a chorus of howling wolves upon activation of the heal( herself howling if necessary).
Either that or God Of The Universe/Junk-O-Tron 
(Literally just an extremely badass model just throwing the most random of things from cleavers to skyscrapers to hotdogs to entire planets)
