I don't think that's a good idea, and here's why: good movie adaptations come from taking the essence and essentials of their source material and making that work as a movie.
Take the Marvel movies, for example. They don't try to completely recreate the Marvel universe on screen, with its decades upon decades of stories, characters, retcons, and tangled storylines. (Sound familiar?) The movies take what makes the characters who they are and create new stories based on that. "Iron Man" changed Tony Stark's origin so he was wounded in selling wow accounts Afghanistan instead of Vietnam, but kept the shrapnel heading toward his heart and the capture that led to get fast wow gold to him creating the Iron Man suit, and so on and so forth. It wasn't a direct re-telling of a story from the comics, it was a new version of that story made for the screen, which is why it worked as well as it did.
A WoW movie made to follow canon directly would, I think, be a mess, because Warcraft canon wasn't made for that. Hopefully the screenwriter can find what makes Warcraft what it is (no, not just big shoulder armor, though I hope we see some of that) and find a way to make it work as a movie, not as a video game series.
They already said way back when that the movie would star none of the existing characters from the games, nor feature any plotlines from WoW. It will center on a human commander.
I think this is pretty much a good way to get world of warcraft accounts non-players into the movie, and a bad way to do a movie for the fans.
They have announced so much of this movie, and it's stopping and starting, and script changes, and director changes, when it's actually in post-production, I will believe it is actually coming out.
While I agree with Jordan Phillips below. I kind of want them to include major characters in the movie as well. I'm thinking Blizzard might see this as a way to open new people to starting the game.
If my friends (who don't play WoW) really like a character in the movie, they may want to see what the game is like. It would be somewhat disheartening (in my opinion) if they then find out that "awesome character" doesn't even show up in the games. It could still get them in the door...