They arent being denied on absolute symmetry. Also the word means equal balance on both sides of a given line, so giving equal opportunity to both sides is an important part of map balance. How the map unfolds is certainly determined on what classes are present. I feel if you give good places for infantry to skirmish, limited calvary lanes, and places for archers to safely shoot at key points while having a limited arc is the way to impose MORE balance than what is there. Perfect balance will never be possible due to the nature of the game. If the sides look similar the map is denied, which is why I think there are fewer city maps in the rotation. These maps are also harder to create in the editor. Several have been denied simply because the sides are too similar.
I really don't have a big problem with the map rotation, but I do feel one side always has an advantage. Either they have to move a shorter distance to the central tower. Their side has a roof with a peak for their archers to freely shoot and have cover, while the other team starts in a field with no such benefit. There is one city map where the team has to climb up a tiny freaking ladder and their whole team can be on the roof infront just shooting everyone that climbs up. The only two other entrances are tiny slits in the outter walls doors that could be blocked by 2 shielders. I could go on and on but the point is I feel there could be a better attempt at balance than what currently is on most maps. Once again I don't think it is that massive of a problem, but it could be better.
I can totally understand not wanting cookie cutter maps because it would feel odd playing it, but you can still impose map balance and make the structures provide aesthetic variety.
