One of the current issues in WoW is the perceived imbalance between the Alliance and Horde storylines. The Horde story, the rebellion against Garrosh, is a more interesting and central experience. The Alliance storyline feels like more of an afterthought. On the various fan sites, many fans ascribe this fact to Blizzard favoring the Horde at the expense of the Alliance.
However, in my view, this story "imbalance" was an inevitable consequence of the Cataclysm decision to heat up the war between the Horde and the Alliance.
In 2009 I wrote a post on The Nature of War, where I said that the modern view of war is "the only moral war, the only just war, is a defensive war." Thus it would not be possible to start a war without one side being considered evil.
Now in Pandaria, we see the end result of that. One side had to go evil to make the war "fit" with modern sensibilities. Thus one of Garrosh or Varian had to go bad, and Garrosh was the one chosen.
That sets up two stories: a civil war within the Horde, and the Alliance attempts to finish Garrosh. Of those two stories, the civil war is always going to be the more interesting story.
It could have gone the other way. Varian could have been the one to go bad, and the Alliance be torn apart by civil war. Possibly with Anduin leading the forces against his father. (To be honest, this might have been a better story than the Horde civil war.) But in this alternate future, the Alliance storyline would have been the more interesting one, and the Horde the ones left behind.
Ultimately though, the storyline would still be imbalanced. The modern view of war demands this outcome. Parity between Alliance and Horde stories can only come when the two factions are not directly focused on each other.