MoP Spoilers (Though Blizz Did Tell Us)
Does it count as a spoiler if they DO tell us?
So, Garrosh is the final boss of the expansion. Deathy is simultaneously elated and somewhat saddened by this. Elated because he gets to punch the jerk in the face, repeatedly. Saddened because, well, Garrosh's story.
He started out as a weepy kid certain that his dad had doomed his entire race, and upon finding out that his father was, in fact A Hero (if for the wrong reasons) and saved every orc (even if he'd been responsible for their situation), young Garrosh set out to live up to his father's shadow, and if possible, be more of a hero and greater than just "Hellscream's Son".
And, so far, he's failed. That's not quite the heartbreaking part.
That part is how he's failed and doesn't understand why.
He is doing things in the traditional orc way, but that is no longer the way the Horde works. The orcs can no longer stamp, roughshod, over their allies, with the rationale "because we're orcs and we are stronger". They can no longer force the "weaker" races to obey - though Garrosh is indeed trying, it's only driven a wedge between him and the former closest of allies the Horde had. His desire to make the orcs the strongest faction on Azeroth is at the price of every other faction on Azeroth, and he sees nothing wrong with this.
He wanted to be remembered as greater than his father; unfortunately, he will be. A greater butcher, a greater monster. His family line will now be remembered as "bad blood", thanks to his own actions. And this will come as a complete shock to him.
As for Jaina...
Blizzard, please. Don't destroy her characterization because "she needs to be more warlike". No, what she needs to be is more proactive in her desire for peace. Send her out to break heads together because they're not listening, but don't turn her into Varian 2.0
Because should that happen, Deathy will be going into his personal headcanon where none of that happened and Jaina is secretly seeing Thrall, and Aggra somehow mysteriously failed to exist.
Okay, rant over.