The AV map is not balanced.

In a PvE race, for both sides and with equally skilled opponents, the alliance has an easier time.
The horde cannot bypass the final bridge; that is the only way into the base.
The alliance can cut up a hill, rather than follow the path in the horde base and bypass 3/4's of the hostile NPC's.
Plus after going through the structure, you can follow the path between the two towers or go to the right and through the break in the fence... then get into the right tower and take almost no missile damage.

In a PvP contest, where a choke is forced at some point and then battle commences...
Either side can hold the hill area around Icewing Buker/Stonehearth Graveyard.
If the offense stops at that point, the alliance burns nothing and cannot take out a Captain... while the horde get to take out Stonehearth Bunker and the Alliance Captain, for a substantial resource lead.
The Iceblood Tower/Iceblood Graveyard for the horde is probably the tightest choke in the game, but the alliance cannot hold it as the horde can run through the graveyard and jump off the edge.
About the only really strong choke for the alliance, is their bridge... which sacrifices the entire map essentially except their final two bunkers.




Basically...

If both sides play for PvE, the alliance usually wins.
If both sides play for PvP, the horde usually wins.
If either side plays for PvP, while the other goes for a PvE race, the PvP side wins.