GAMON-2013 "I've been eating a lot of porridge so don’t get me mad!"
Personally think they have already chosen the new Warchief a while ago, we just have to wait and see.
I'm an altoholic since 2005.
Alright I can't keep this secret forever. I am the new War Chief. Yes I have taken over the Horde, in the name of the Alliance.
The day when the next leader dies is already set.
Metzen would sure have fun to triple his work just to make a vote possible (and throw 2 developed paths away again). Not to speak of how it would delay the content-team.
There's most likely already been tons of story written out that includes whoever Blizzard has already chosen to be warchief. Even if they let the community decide, they'd most likely have to completely change around a lot of next expansion's story and details.
What if they've already gotten enough writing done for it (you know, far enough that it's already into the next expansion) that player choice might conflict with what they've already got going. (Only the South Park guys can work that fast.. lol)