I've heard the WoW movie was really good.
The issue is bridging the gap between fans and newcomers, and potential non-gamers. Frequently, game movies try to water themselves down to the point of wide reception, leaving fans unhappy. But this still usually doesn't work since newcomers aren't as attached to the franchise, so unless the movie is absolutely amazing, it's still probably not gonna stick.
But if you just market it towards the fans and try to help newcomers catch up, it has a lot of potential. Might not be the most profitable movie ever, but it could at least be good.