Ideally the jury would consist of map makers, as well as pros, and players of various ranks, so that the map appeal to a wide range of people, with a competitive playability, while favoring interesting and different layouts which would be recognized more easily by mappers.
Also, map makers have a particular eye on things such as polishing, they can see more easily if a map is really well thought, through how it is optimized, and even through the brushwork. This can help choose between two maps both great gameplay and aesthetics wise. Maybe that's part of what you meant @Oliver?
However, @text_fish, one could argue that probably half of players play either dust2 or mirage ![]()