Originally Posted by bobTHEsnob
This is an illposed problem. The issue is the following: A player can be excellent at playing a particular champion in a certain role say mid as veigar, but be forced/chose to play his new champ Nautilus as support in a different game. Say his elo as veigar mid belongs at 2k. It i very possible that his true elo as Nautilus support is 1k. And so said player hovers around 1500 elo and absolutely owns half the games and feeds like a monkey the second half. Unless I am very mistaken by the time he has mastered nautilus as support he will have discovered and bought a new champ UnknownBadJungler which he decides to jungle. again suppressing his elo sub 1500 inspite of his veigar mid skill. Since the skillsets required for different champs and roles varies so much, it is very likely that the problem is only solvable by attaching individual elo to the champs which would be difficult as the game is set up...so...no easy solution here. Even amongst the very top players few(read: none) play all the roles even close to equally well...
You have fair points; however, underlying player skill does carry over across champions. For example, a 1800 player might be a 2100 Annie player, a 1500 Vayne player, so on and so forth, and the representation of his skills across champions is 1800. When this player plays a new champion for the first time, he might be equivalent to a 1500 player on the new champion.
Now, let's compare this it a second example. A 1500 player might be an 1800 Vayne player, a 1200 Volibear, so on and so forth. The representation of his skill is currently about ~1500. When this player plays a new champion for the first time, he might be the equivalent of a 1200 player on the new champion.
So yes, I agree that player skill varies across champions; but, I think some amount of player skill does transfer across champions since afterall, there are a lot of basic mechanics and skills you learn in League of Legends that stays with you, the player and not necessarily tied to the champion you play.