A possibility to configure for each map: a minimum and a maximum playercount, which is then used for the mapvoting. During each map the players are counted, the mapvoting uses the average from the past 3 rounds. (Maybe this can be a cvar? never thought it out for coding in a mod, more for lua or an external tool moving the pk3s around..). For example, having 10 maps in etmain, 3 big maps, official (6maps), and 1 small map. If nothing is configured for a map, min would be 0 and max 64. With this its possible that no map would be available under certain circumstances - when wrongly configured.