What if Blizzard made the factions be determined by ideologies instead of race? Any race could choose any faction upon character creation.
Alliance being defined by honor, sacrifice, rule of law.
Horde being defined by pragmatism, freedom, anarchy.
This will give players full freedom when choosing a race, and not force them into choosing a certain faction just for wanting to play a certain race. This will also make sense lore-wise after the recent events in the lore. And it will also do wonders to faction number balance across various realms.