Clients should report to the server if their configuration prohibits them from downloading maps they do not have available, and this message should be spread to all connected clients. This way it would be easier to sort out problems which are induced by single users' configurations causing them to be unable to download new game data.
An even better implementation would track and show, during the game setup, whether all connected clients have all the data needed for the current configuration available. This could be done by adding another player readiness state which overrides the user set ready state while not all data is available on the client, and automatically switches to ready as soon as all needed data is available on the client.
