So, my reckoning is that it'll have to take a certain chunk of WoW lore and focus on that. I suspect it'll be something that's already been written, as new invented lore that either takes place after the current story position or is tangential to it risks causing problems in future. I think it'd be really cool if, for example, the WoW film took a story that players had just a tiny taste of, like the story surrounding Theramore, and made it into a film. Yes, the book already exists, but I can't imagine that the numbers who have read it would equal the numbers who would watch the film.
What do you think? What do you suspect might be chosen for the film's storyline, and what do you fear? What would you love to see, and what would annoy you?