Upcoming arcade/battle boss skins

With the new Arcade Riven and Battle Boss Blitzcrank splash arts there seems to be three spaces left for battle boss skins and one more spot for an arcade skin that players can pick. This could mean more for the skin style or just something riot put in the splash art for fun who knows, but it does make me think that arcade/boss Zac, Ezreal, singed, or even Oriana could be new skins. Why I chose those champions are because i have seen some people drawing splash arts for them. What champ do you guys think would make a cool battle boss or arcade skin or am I am just crazy about this whole concept?