Nalak must be defeated in order to access the single-player scenario boss, Shan Bu. After Shan Bu falls, Perculia describes a particularly interesting scene as taking place:
You don't have much time to rest though because the Alliance and the Horde are about to wage a war in the courtyard. While both sides have good reasons to fight, Taran-Zhu forcefully puts an end to the conflict. Both sides reconsider, draw a tentative peace, and focus on the common goal of saving their energy to take down Garrosh.
It would seem that this is the patch in which the secret alliance between Horde dissenters and the Alliance itself is formed--at least tentatively. That would seem to imply that beginning with patch 5.3 we'll start to see this plot taking shape, and doubtlessly we players will have some major roles to play in its execution. I'm not going to lie, everyone, I'm totally stoked for this!