Arcade Lee Sin and Rek'Sai...yes I know they're fairly popular but plz listen.
Lee Sin: He will be based off fighting games. His design will still be similiar to the other arcade skins (basically the disco 80-90s gamer type of look) but his moves can be based of fighting games. For example Q is a hadouken and Q again is a hurricane kick but has it slightly titled to make it not too similiar. When the match starts or he respawns there will be an announcer with pixel text saying (ROUND ONE! FIGHT). He can have a victory screen for a taunt, with him doing a pose, holds it and a chat box pops up that spawns text that he say to the opponent. He has alot of potential for a recall animation. Such as Continue? (9, 8, 7, 6, 5, 4, 3, 2 - CONTINUE! recalling) or Time out! (announcer: TIME OUT! PLAYER TWO WINS! ROUND 2. FIGHT! recalling!) or him simply spawn a arcade cabnet (MORTAL KOMBAT STYLE!) and he plays it as he is recalling. Just to give you some ideas.
Rek'Sai: You know that pixelized baron thingy they keep "using" with the arcade skins? Well they don't actually uses them on the skins themselves. So I thought, what's the closest thing to Nashor if we're talking champions? And I immediatly thought of Rek'Sai. So I thought Pixel Baron Mask + Rek'Sai= Arcade skin...but it had to be based on something. I thought Rek'Sai could represent a typical RPG boss. With generic 8-bit main characters desperately trying to beat her during her recall animation. Call her...I dunno Difficulty Spike Rek'Sai. Underground (I know you can't draw this but) you can hear music playing like a random battle incounter like Final Fantasy or Pokemon? Show a text boxs to tell what ability she is using as well to make the damage indicator both bigger, pixelized and visible to your opponents. Also play victory music when she dies, as to replicate classic boss battles.
...Oh no. I went on a rampage huh? >_< I was just to give you an idea of the skin idea and I went into a writing spree. Well I don't want to force you to make these. I just really am intrested in how they would look. I didn't tell you how they would look did I? But Lee Sin and Rek'Sai are fairly popular champions. Oh well. Atleast I shared my opinion.