Surely you have some very hard evidence to back up this actually occurred other that flaming about what has taken place over the forums in the last year plus. Wrath was the games heyday, Cata is where things started to turn for the worse lack of endgame content really kill the game for a lot of people outside of the raiders over course. The social aspect has been much to be desired since cata as well, some of this was of Blizzard's owning doing with simplifying revamp zones and remove the elite quest in the world.
You’re like the current president, throwing around the word "Period" like your some statistical expert. There tons of reasons people leave a game, some come back every now and then give the tires another kick to see what has changed. A lot of people have grown old of play a game that requires more time than most other games to play. Others just want to do more than play a game, period.
I know for one, I play less now than I played 8 years ago. Is that because due to the content or life? Life has to be prioritized when one has a career and a family. I tend to get off the chair more now and spend time with my wife and kids. My children are in their teens and we can do a ton of things together now, that we could not do when I started this game 8 years ago. I am sure there are a lot of people like this, matter a fact I have met a lot of them through the game.
You do not know what you’re talking about, from an esthetic and tech standpoint MoP is amazing. You chose to look at from the prism of a panda and can't see past that, what a shame because the devs did a tremendous job on the visual aspects of the game. I like they are going to have even more Easter eggs in WoD for the people that explore the world they create.
Try looking a little deeper in the game you play past the quests, raids, and pet battles sometime. It is an amazing world Blizzard has created for you. I for one appreciate everything they have done over time to make life easier all the way down to the simplest tasks.
So saying they are hemorrhaging subs do to MoP, well maybe a few just could not see actually past the panda’s.