WARNING: this is PURE speculation, read it with a very large pinch of salt and do not blame me for not reading this first paragraph.
This has some very very big spoilers in it this video, for instance. we currently know the end "boss" of the expansion is garrosh, and now we've gleaned that he is attempting to control the sha energies. to me this absolutely SCREAMS that he is going to become corrupted by sha energies (with his anger and rage.. its beyond plausible). so the end raid on orgrimmar could very well be sha-themed. this really is an interesting twist to the story, and would be an ideal ending to a tyrant.
secondly, such an act as this will greatly make the other horde leaders doubt garrosh, even further than they already have. this also leads me to believe that this could tie in with the above, and that the other horde leaders will band together to face off against these type of "war crimes".
very interesting find OP, thank you for sharing! blizzard has done a good job with this.