Here's a fictional GvG scenario.
One team's guild hall has all the normal NPCs. ~12 archers, ~3 footmen, 2 knights, bodyguard, guild lord. The other team has ~12 archers, ~3 footmen, 2 knights, 2 curse necros, 4 blindbot/sirspike eles, and 6 bodyguards. Guess who wins?
The two extreme maps in Alliance Battles (Ancestral Lands and Kaanai Canyon) give us the same scenario. One team always starts with somewhere in the neighborhood of 8 extra NPCs more than the other team (NPCs which cannot be captured), which happen to be placed so that they defend 2 shrines and 6 extra NPCs that can be captured. Playing on these maps is not fun. The same way fighting a 16v8 in tombs is no fun. When one team has a guaranteed 2 extra shrines and the other team has no advantage, can you call that balanced pvp?
The only possible way to win these maps is if the defending team has at least twice the amount of mentally retarded players on their team than you do, which although happens sometimes, has nothing to do with strategy or execution. Since coordination between 3 separate groups is impossible, winning this map, for the most part, is a random event.
Aside from the inherent "auto-win" these maps give the defending team, it's annoying to hear the "LMAO YOU GUYS GOT OWNED 500-300" from players whose combined IQ is less than a chair's.
Take Kaanai Canyon and Ancestral Lands out of rotation. The other 3 maps are more fun, require strategy and execution, and give both teams a nearly equal chance to win.