I will remind people that this is a Warcraft movie, not a World of Warcraft movie. I'm not distinguishing the universes like some stubborn purists do, but the movie could be about _any_ point in time in Warcraft history.
I think it will be Alliance focused (viewers relate to humans, not green orcs, yada yada), but I don't think it will be the Arthas story line. I'd _like_ to see the Thrall/creation of the Horde story line, but I'm not sure how people would react to a live action movie featuring CG character as the lead.
I hope they don't totally _make shit up_, but Chris Metzen and Blizzard are heavily involved in the movie so I doubt it.