While I agree with the complaints that an average wouldn't be *exact*, I still think it's a better indication than nothing. I think you guys are talking about outliers.
Also, in response to the queries about number of active games: I don't want to know how quickly someone plays, I want to know how quickly someone plays *each game*. I don't think that doubling the number of games will double the number of moves, but if it does then clearly that player isn't playing too many games.