http://www.youtube.com/watch?v=yYLze3dIt5s&feature=feedu
I honestly think everything he said in this video is true. People who are saying WoW gets boring are saying that because the game is becoming too easy. I'm not saying it's very easy to achieve a lot in pvp or pve, i'm just saying that more and more "bonus features" that allow us to play more easily are being added continuously. I believe the changes that have been going for few years like heirlooms, guild skills and stuff are more for new players but it saves much time which leads to people having not much to do and quitting. Even leveling should be without any boosts so it would take more time.
If it's harder = it takes more time is basically my idea.