How do you think the game would be affected if one player was able to see a top-down version of the map and could make suggestions to the players via the map. He can see his players on the map, and would be given access to 180 degrees in front of the players on his team; he can see dots of the opposing players if a player on his team can see that player. Using this information, he can make suggestions to other players via mouse to arrange flanks, etc?
It would add a very interesting element to the game, much like an RTS. He would be very busy with 4 players to control and coordinate.