Fun but unlikely addition: "pre game" champ interactions
If you've played overwatch you know exactly what im talking about, otherwise for anyone who doesnt know, in overwatch the heroes will sometimes exchange a few lines, some idle chatter during the setup phase. What fun interactions could our champions have before the minions spawn?
and 
pretty much have at least one special emote for all champs. Recnetly Skins also come with a lot of special interaction too, Star Guardian 
was the more noticeable one with her quote.
Unless you are talking about them doing it automatically, I guess that can happen too