Not-so-short but meaningless blogpost:
Skins. All of them. Existing skin themes (Guardian of the Sands, Eternum, etc.). Expand them with more skins. Here are the ideas.
Here we go
Legendary skin. Sejuani replaces her trusty boar with a badass Motorcycle (with metal tusks, because she still likes pigs). Sejuani comes with a spiky leather jacket, torn shirt n pants and one of those stereotypical biker helmets (the round, soldier-y one, with the little spike at the top) Effects should include some sort of smoke, chains, and/or fire.
Alternatively, can be adapted into th "Road Warrior" theme
Since that's a thing now, prehistoric Sejuani fits perfectly. Put her on a Triceratops, Chasmosaurus, or Styracosaurus, and give them the same kind of bronze/copper armor that the new prehistoric skins have. Lots of potential to be creative about this. Possibility to change particles and sounds effects to go into a rock/jungle theme. If not, then just 750 RP and make th dino blue/grey like Anivia, to keep the ice theme
Alternatively switch the Dino for a mammoth, although that's way less cool and we alread have Sabretusk.
Riot loves sand-themed skins and spits them out like a redneck family spits out offspring. The Pharaoh skin line is an old one that is only occupied by Nidalee and Amumu, but it has a lot of potential. Karthus can also easily be imagined with sand effects. Just put swirls and dust over everything and make his wall's obelisks actual egyptian ones. Also, his staff works as an egyptian sceptre. Probably 975 RP.
Alternatively can be named "Risen Karthus" and adapt a more mummy-like theme
Just for the lulz. Can also be called teacher, the basis is the same.
I just want to see Nidalee turn into a raptor. Legendary skin or bigger, since it requires a whole new cougar model. Nidalee herself can also be imagined in the bronze armour with primal headgear (there is a low elo joke in this, but I won't use it)
Why not? give him different animal skulls as headgear and use the metallic-Predator theme from the other ones. 750-975 RP, depending on effects.
Purple, yellow/goldish, Pink
Maybe even for one of her skins, possibly Bloodstone. I just like Lissandra and would love to see more colour variation (given that it comes with differently coloured spell effects as well, in which case they'd be more expensive than the regular chroma packs)
Graves in one of those oldschool-british safari outfits, complete with classy beard (the sideburns-mustache one) a safari helmet and a fitting double barelled Blunderbuss (is that what they're called? I have no idea) + monocle, for extra classy, 750-975Rp depending on recall animation
Creepy Anglerfish theme, fll with a that lamp thing hanging from her head and pupilless eyes. + darker effects on water and fitting /joke fishies.
to share a theme with Fizz (because i presume they are at least f*ckbuddies). Orca-coloured tail (conveniently the movement stays the same, unlike the much wanted Shark Nami, which would require her to get different tail movements to be authentic). She also dons the same polar hood as fizz (with extensions for her...."hair"? Her staff becomes a harpoon thingy, and her spells get icy effects (E indicators aren't bubble but ice chunks) added to them (+ possibly a giant orca whale appearing in her ultimate's wave)
Potential details would be white spots above or around her eyes (to match Fizz, and orcas in general)
-Guardian of the Sands
Sandy Malphite, with a small obelisk or pyramid on his back. Needs a VU before that tho.
keep the bird theme, red and orange colours and fiery effects. Simple but effective
because there are never enough birds. Similar to LeBlanc, with that dark, blackish theme. Scary armor and soldiers
Quinn in a suit with shades...Valor gets them too. Her weapon becomes a gun with a silencer. Just a fun skin for 750 RP, 975 possibly, if they add different aa particles and sounds.
I just need an excuse to make her ult call down a goddamn lightning strike. Lightning particles for the remaining abilities too.
We all know he needs it.
My favourite ADC needs more love...and skins...and this one is overdue.
it's Aztec themed. the Aztec god Quetzalcoatl, the feathered snake. Need I say more?
Elise is now a Scorpion. Her E now burrows her underground instead of lifting her up into the air. I don't know how it's supposed to work, but MAKE IT HAPPEN.
Buffs first tho, she needs them.
Famous last words
This is all I've managed to come up with for now. there's probably more somewhere in my brain, but I need to sleep now. Feel free to leave your own suggestions, but rememeber that it's only about EXISTING skin lines.