Alliance is- regularly winning AV now?

Wrong. Starting short had nothing to do with queue syncing - it was a bug. Teams starting with fewer that 20 players was a separate fix.

We’re fixing a setting that allowed the battleground to start with as few as 20 players on a team.

https://us.forums.blizzard.com/en/wow/t/alterac-valley-adjustments-incoming/422125

And btw, last week I was in an AV that started with 24 players. Alliance never had more than 32. I would say starting a match with roughly half the players isn’t a “fix” but that’s Blizzard for ya’.