(Disclaimer; I am aware that I might be infringed for some of my analogies, and if I am I accept it. I do apologise if I am hurting anyone in person, but I feel this is relevant to the discussion on Varian)
Zoombini; George Bush and the War on Iraq has a lot less support now that the three days of butt-kicking is over, and people have to face the reality that is left in it's wake, than it had just after 9/11.
I have personal reasons to dislike Varian because he acts like the captain of the football team which I always found to be an ass-backwards douche. Livejournalism aside, it is bad for the state of the future of Warcraft if Varian is allowed to dismantle the "status quo" of the current faction line. There is a reason why we don't have our world turned upside down, there is a reason why the warsong, arathi, alterac conflicts don't lead to bigger squabbles. By this I refer back to the points of the Tauren, the Darkspear Trolls having sworn allegiance to Thrall, not to just any orc, and both of these people seem (with the exception of the Grimtotem clan) to be caring about their future. In short, they'd avoid bloodshed because it's in their nature (Tauren) or because they're too few (Darkspear). The Forsaken wouldn't stand a chance versus any other faction in open war, especially not at the given time, so they'll not have much of a say in the matter.
Similarly on the Alliance side, there is nothing (as far as I know) that states that the Night Elves (bar Staghelm, but Tyrande and Malfurion hold too much influence over the Night Elven nation) nor the Dwarves that would follow Varian blindly into war without exploring other options first.
So, let us assume that Blizzard is interested in making money AND writing a good story. In order to make money, they must write a good game that reaches out on not only the technical and mechanical level but also attracts players based on more than just gameplay. Let's face it, we wouldn't pay a monthly fee to play an elaborate version of Tetris with IRC embedded in it..
In order to keep a large number of people coming back (those caring about storytelling), the world Blizzard creates must respond to what those people want when it comes to good storytelling, and to be bombastic, good storytelling is not rebuilding Iraq.
Good storytelling is not going over the boundaries and throwing everything that everyone related to up to that point out of the window. I am very excited about what Blizzard is going to conjure up next, what 3.2 and 3.3 and any surprise raids (Sunwell style) after that can bring us. But I am one hundred percent sure that if Thrall is killed off or Varian actually did go into open war instead of just "bickering" on random run ins with Horde leaders, we are going to have a massive amount of players protesting the oblivious retcons (Tauren and Troll allegiance, Dwarven sovereignty, Branns indisputable influence on his brothers, Malfurion and Tyrandes friendship to certain important lore characters that WILL be opposing such action) on a scale previously unseen.
Long story short; Blizzard has to act delicately. The clichés must at some point either die out or they will strangle everything from the Wc3 demo and up till today.
(note; I've left out Velen in the argument because I'm not sure on his position, except that I don't think he'll be interested in global warfare when he is very much personally aware of the danger Azeroth is in from the outside.)
EDIT: Grammar. Also, please jump on this post and dismantle it, I am looking forward to replies or comments on how wrong I am, and why.