Achievement Skins
How cool would it be to have borders, icons, wards and emotes based off of your achievements in game. Unlock the "Give me the Penta" border by getting a pentakill and paying the required rp/be. Unlock the "Mine all Mine" icon by getting every dragon in a game and paying the rp/be, etc. I think it would make for a more interactive experiance that would push people to achieve and learn, as well as show off something to their friends.