Why Hide Elo?
The hidden variable referred to as 'elo' or 'mmr' (match making rating?) influences how matches are made. It is also balanced such that we roughly win or lose 50% of our games. However, the variable is hidden. Which sucks, since oftentimes we have friends who are not in our ELO, whether higher or lower, and playing with them, or talking with them, is like playing or talking about a totally different game.
For example, I would tell my friend about a champ I want her to play and tell her how good I did with that champ. But when I'm top, I fought a Shen or a Tahm Kench or a Gangplank. Meanwhile, when she was top with the champ, she fought a Tryndamere twice and a Fiora. Worst, I remember a time when I only saw Katarina mid--but now never see her, only to find out my friend sees Katarina fairly often. So what's the point of hiding ELO? Particularly if champion diversity is ELO specific, to the point where each ELO is a radically different experience (as champions in game make a radically different experience [e.g. a fed Lee Sin and a fed Khazix have two different feels].)