Because of the population difference and how the queue system works, the current situation on the PVE server for Level 60 battlegrounds is that there are constantly 1 more Alliance playing, except in the (relatively rare) cases where full 10vs10 is achieved.
A typical example is that 6 horde players are queued and 9 alliance, so the game ends up being 6vs7. If 1 more horde then queues at some point during the game, the game is 7vs8.
This gives the higher population faction a permanent advantage and is detrimental to a fair battleground experience.
Therefore I suggest that the battleground queue system is changed to allow only equal number of players in.