Mastery skins
I think it would be wicked cool to implement mastery skins for each champ that you unlock at mastery level 7. Obviously it would take a lot of time to create a skin for every champ but I think that would be a nice reward for reaching mastery 7 along with the emote and banner. Other games like smite have something like that but it's just gold recolors of the base models. Riot however actually knows how to make skins and I think they could get really creative on them, maybe lore based skins or something, what are your thoughts on this.