hmm, interesting. i did mean to say that this is a problem more in the context of games that add tiers/divisions to their ranked ladders, but i hadn't really thought about elo making assumption about the normal-distributed-ness of player deviation from their "true" skill level. does that not just fall out directly from the Central limit theorem (given the taking of large #s samples (game W/L observations vs. predicted P(win|my elo, their elo)) of means, etc.)?