Our $15 subscription fee is paid so that the WoW devs develop new content for us. However currently, all the WoW devs are working on MoP, which we are expected to pay for. If you are subscribing to WoW right now, all of that money is being used to develop content that we are going to have to pay for. Why should a game with a subscription fee charge for expansions when subscription fees should pay for content development?