>>717754463
Either let every race choose a faction, or get rid of combat racials (may be too late).

Racials and Blood Elves skewed the balance to Horde after Vanilla, and by the time they compensated, people were entrenched in the Horde. Alliance racials are better now, but raiding guilds don't want to go through the mess of changing factions of all their people's characters and alts.

You could do it like Pandaren where you choose a faction after completing their leveling zone.