As much as I'd have liked them to use the original logo, or at least an updated form of it, they couldn't really. It screams 'geeks in a basement playing boardgames', which when trying to sell a movie to the general public, isn't a great attribute.
That said, I don't like the movie logo at all. It's very bland and defunct of any personality, and doesn't have a distinct Warcraft feel at all. It also seems like the kerning is off either side of the C.