This is getting ridiculous, somehow, in some way, there are some alliance players never getting over the idea that when alliance lose (and it’s not always that they lose now, not even 8-9 out of 10), it’s always the fault of something else other than the horde simply winning those BGs. It’s always the map or the racials, never anything else. (The OP did say “4 or 5” that is won due to being beaten, but the focal point is still strongly focused on the map and the premades becoming harder to form, so the subtext implies this “4 or 5” is not genuinely meant.)
When push comes to shove, horde players got a lot of people accustomed to facing premades, which required trying harder on average to squeeze as much honor as possible out of every AV. Because the only other option was to wait for a long queue timer and then lose fast and barely get anything, which isn’t really a valid option.
Meanwhile, the alliance premades created a HUGE segregation in their player community. On one hand you got the super coordinated premades, and on the other you had the leaderless players and generally just the people who never measured up to be in a premade, prone to asocial behavior.
So the “second class citizens” that was created on the alliance side, never got used to winning. To even try to win. They never got a game plan to get used to.
This is now the difference you’re still seeing the effects of.
However, the fighting strength of these “second class citizens” on the alliance side, has actually gone up now. Because they get mixed with those former premade players calling the shots. Because they see a reason to try harder now. Because they are properly incentivized now.
It is not going to be a change occurring over night. Alliance lose more than the Horde does in AV, and that’s that. But this is not a constant. It’s highly susceptible to change over time, even different waves of players trying to rank up will significantly impact these patterns, because not everyone plays equally well. It’s highly individualistic.
So as these second class citizens now gets something to get used to, they will also improve over time. The same way the horde players did, when they UNFAIRLY had to face those huge premades when they could only queue solo, all the time.
It’s nothing but a problem of your own creation.
Meanwhile, the long AV queue times for horde are still serving as a stronger motivation to win in AV than the quick queues for alliance.