With 40% of responders wanting multiplayer it's a must at this point. The next stretch goal, mac porting, caters to ~10%, and a later one, linux ~5% of potential customers. For those complaining about development time, why complain about multiplayer when porting will take up more development time anyway? Go rage against that. Look if this is done anything like the IE games, multiplayer will be awesome and seamless from the singleplayer.