Let's just cut to the chase here: It was revealed in the press event information that Garrosh Hellscream, current Warchief of the Horde, will have his reign abruptly ended in Mists of Pandaria. The son of the great Grom Hellscream will no longer be Warchief, and it's not only the Alliance that will be participating in his dethroning -- it's the Horde as well. Though it may seem like a rash course of action, in all honesty, this has been coming for a very, very long time.
I chose Garrosh because he has the strength to lead our people through these trying times. For all my supposed wisdom, there have been moments that I've barely been able to hold the Horde together. The Wrath Gate and Undercity displayed that clearly.
The Horde cries for a hero of old. An orc of true blood that will bow to no human and bear no betrayal. A warrior that will make our people proud again. Garrosh can be that hero. I did not make this decision lightly, Vol'jin.
I know our alliances will suffer for it. I know the Horde will be irreversibly changed. But I made this choice with confidence that Garrosh is exactly what the Horde needs. I'm trusting you and the other leaders to not let this divide our people. You are stronger than that.
After all, he is the son of Hellscream.