Once upon a time in vanilla WoW, there was a very different view regarding the ongoing Alliance vs. Horde debate. To Horde players, the Alliance storylines were interesting, complex, and contained epic moments that had to be seen to be believed, like the original reveal of Katrana Prestor's true identity in Stormwind. The Horde had no equivalent to this, and thus it was assumed that there was undue Alliance favoritism going on.
It sounds weird given today's somewhat more balanced treatment of both Alliance and Horde stories, but there it was. And when you look back at the original release of WoW and the story behind it, you'll see where that viewpoint came from. Even though the Horde had their own storylines, those stories were basically branching off from the far more epic (in the opinion of some players) Alliance versions.
What was the Horde all about in vanilla WoW? ... oddly enough, the Alliance.