https://i.imgur.com/IqYTuS5.jpg
I can't be the only one to have seen the similarities. Can't find too much discussion on it though.
So if it wasn't clear I'm saying that while the Alliance symbol is clearly a Lion, I think the Horde symbol is a Void Lord.
https://i.imgur.com/Y3vrbgv.jpg
Now I don't know enough to go into speculation about the ramifications of this. There is trouble differentiating between the sinister Void Lords that created the Old Gods, and the void lord blueberry warlock pets.
That said I can't help feel that Alliance are pitted against Horde again and it is coming down to a battle of Light vs Shadow.