During the launch of AV, queues were nearly instant for everyone and Ally won in roughly 8-10 min each game before Ally AV Premades. Once many people got the rep rewards, and Horde began countering the zerg more, relative Ally participation began to drop.
Since then Horde queue times have continued to increase, indicating Ally participation is continuing to decrease.
In general, Horde players enjoy PvP while Ally players enjoy PvE. The queue times will always be shorter for Ally, with a possible lower win rate overall; whereas queue times will always be longer for Horde, with a possible higher win rate overall.
The best solution is to make a Premade and only queue with them for WSG/AB. I know this is parroted a lot, and know not everyone wants to Premade. However, it is likely the only solution if you’re looking for shorter queues outside of rerolling Ally, which comes with a 100% loss rate in AV. I feel it is highly unlikely that Blizz will revert the East/West split. But there could be a possibly of it due to the general negative feedback from the change.