Why not leave players the option of having multiple accounts?
This would of course require changing the matching system so that multiple accounts by the same player can not participate in the same game, but that should be an easy modification.
It might for instance be useful to have couple of accounts, some in which the player is competitive and the others in which the player plays more casual games.
Given the current pointing system where players lose more points against lower ranked opponents, competitive players are forced to play with high point opponents, but high point players are quite difficult to find for a quick casual game. If it were possible to have a second account in which the player is not competitive, he/she could find a quick game with an arbitrary opponent, without worrying about the opponent's points...
Many games with ladders allow for multiple accounts (e.g. almost all rt's i know of: WC3, SC,..).
