WoW is categorizes as massive multiplayer online roleplaying game. But in reality, WoW is an sport game, like NHL-series or something along those lines. People play wow to compete with everyone else, people want to be superior to others by achieving raid boss kills before everyone else, or they want to get good ratings in arena. The whole wow is centered around peoples own need to compete with others. Game is full of minmaxing to get the win. The leveling part of the game is just hinderance.
I do not see anything roleplay-related in wow, but instead it fits perfectly in the sport game genre.