Originally Posted by
Gregz21
This imbalance has been discussed numerous times, but never acknowledged by Blizzard. Only once have they commented on the issue, saying their statistical data suggested no imbalance at all... and that's it.
The main thing is that the route to the enemy boss is faster and SAFER for ally. If you're horde, you get hit way too often by npc arrows, eventually killing you or weakening you enough to be killed by defending players. Also, the ally base is protected by the narrow passage and by the bridge - 2 choke points that don't exist for the horde base.
Once, in early cata, played AV on my main both as alliance, and then horde, on the same day (faction change). As ally I could get to the enemy base and cap towers at 80% health, as horde I was killed by the arrows already on the bridge... both runs with exactly the same character, no enemy players hindering my passage or anything else, just npcs.