Orc girl gets put in water beacuse orc does not want her to be rasied there beacuse of X, or she has to be sent out on the river to avoid meanie orcs, she is raised by human(s) and somehow is the chosen one leading/helping the horde. Scourge or some other enemy is rising up and want to kill all orcs/humans, orcs and humans have to band together and fight off the enemies with the help of orc-girl and random human mage/warrior. There is infighting in horde/human camps and people disagree with banding together with the other side. This is what the first movie is probably about most of it, overcoming the differences between the races and in the end teaming up. Since there is a trilogy a unspecified amount of what i just mentioned will be in one of the movies, or stretched over three of them. After seeing the trailer, i think that it will just happen in the first one.

WoW is big, but when you are telling a story you cant do everything WoW does in the game, its to big for that, you will have to focus the story to certain things to make a story that people can understand, relate to and "get", like all stories does, or else it will be "all over the place" or just "generic fantasy movie", i hope the movie is good since the animations are really good, but the story will be a dealbreaker for most, and hopefully not just WoW fans will like it, or that just WoW fans like it and nobody else gets it.

The movie can be good, it can be bad, but story wise i dont think it will be anything special at all. Hopefully im wrong and what i just said is wrong and im suprised by the movie. Also this is pure speculation and its ok to disagree with me about this, its only my thinking after seeing the trailer a few times.

They also referencing/borrowed from LOTR in the trailer, when the guy jumps from the tower onto the eagle, almost the exact same angle and everything that Gandalf does in LOTR:TT.