I never would have even thought of using WOW as a learning tool in schools until I saw this post and student responses given in the project. This is the kind of outstanding risk I like seeing teachers taking to incorporate technology in the classroom.  While there should be caution when using games like this that have violence included, there is a great deal of learning involved, especially in communication with a game like this.
I too play WOW from time-to-time during breaks from school and when we are not busy with family stuff and I will say that there is always a lot to learn in this game each time I come back and play from taking long breaks in between.