Looking at the audio from the new 5.1 datamine it seems to me that Wrathion is playing both sides to go all out, while at the same time fearing what war might do to Pandaria and the rest of Azeroth if Sha gets out of control.
He speaks of the King Varian being a principle man and questions if that can win the war for the alliance and praises the alliance champions in conquering a battle with the horde. Wrathion also asks if the Horde is strong/good enough to rule all of Azeroth. He praises The horde on defeating the Ally general and asks to prove ourselves again to him.
Here is the question. Why is he motivating champions (us) to prove ourselves to him via the Horde vs Alliance war while at the same time warning us of the consequences of our war and the Sha? It seems to me that him playing both sides and escalating the conflicts will breed Sha. Is his hopes that our war will take out powerful players on both sides to allow him to make his move on the battered Horde/Alliance with limited resistance?
Now we know Hellscream will fall and reason is (most likely) sha corruption in attempts to control its power. Now you have to ask yourself this...did Wrathion want Hellscream gone and he did it by pretending to side with you and let the consequences of the war play out?
If you did the rogue quests/paid attention to them, you would know that from the get-go Wrathion wanted anything that posed a threat to him eliminated. Wrathion was also for quite some time on Pandaria before we arrived. In this time he might have devised a plan to weaken both horde and the alliance by adding fuel to the fire so-to-speak.
One might say that he wants us to prove ourselves via conquering the enemies of the Pandaren and slaying the evil that plagues this new land!...however Wrathion does not seem to be the "saving" type...not to mention if you think about it we also what plagues Pandaria with our war as well so...yeah.
Thoughts on this?