To each their own.
However, I wish to broach this from two different directions.
First off I will state that I am a WoW hater. I hate what it has done to MMOs, I hate it being overglorified, I hate it pandering to the lowest common denominator and built on instant gratification in what ends up being the MMO equivilent to Kindergarten. With that said, I am realistic. It doesnt have as many players as it does without reason. It is clear there is a lot of work put forth by Blizzard and for the most part you can tell they do at least strive (even if they fail) to give customers what they want in an MMO sphere.
Now, with all that nicely worded vile out of the way, The two ways I want to approach.
First is why I quit playing in a truthful manner devoid of the reasoning above. I quit after Lich king (but I didnt even really start till the end of TBC. I basically leveled one toon to max and felt I "beat" the game. What sincerely drove me to quit (not counting real world issues) was the one thing people claim they cannot break away from WoW for. The community and the friends they made, and the second family/socialization aspect of the game. Something not unique to any MMO as its the truest strength of any MMO.
What I could not personally resolve is in my march from 0-end game I basically soloed. I am an old school MMO soloist. Basically I play to meet my agenda, However, I like being in an online setting in order to pass the time via chat socializing. That way if I am working on something solo, and joking around with people, and I hear guildmates doing something that sounds interesting or I might be able to assist with, I might offer my help, Or I might sit back and wait to see if any slots needed filled. Usually if someone asks, I would be more than happy to drop what I was doing to help someone else out.
Thats the exp Ive always had in MMOs. However, despite going through half a dozen guilds in the course of a year and a half trying to find a good socializing fit, I never could find a match, and the problem was always the same... People in WoW take the game Waaaaay too serious and despite being in a chat with guild mates everything was always SRS BSNS. It was like pulling teeth to get people to joke around, or even remotely get into being in a fantasy world. It was all dry, humorless, mechanical, Boring.
So yeah, the one thing that people point to what draws them back to WoW, the socialism of the game, I found incredibly lacking and what I got to exp, of the community downright unpleasant to be around. It was as if people would not say anything, unless they had a justification for speaking up. And really even being in social guilds, thats not really acceptable, and this is coming from a soloist. Thats sad.
Now the reason why I think there is an Exodus. What we see with Pandaria is just the circle of life of the King of MMOs. They get massive in scope, drag on to the point the fan base becomes unhappy and start looking for greener pastures. When they try, they find the new fling didnt have the same thing as the old love. From here it goes back and forth, up and down with subs, friends drop off, return, drop off, return again. People take extended time off for Key games like a month off for Dark Souls/Skyrim.
Eventually though, it gets to the point of exodus. Its natural. No MMO can stay on top forever. Even if nothing new comes along to knock it off the top after 4-6 years the game simply cannot compete with all the other options and not being drug down by the base/original code limitations. For example with WoW, 6 years after, With games like TOR, GW2, DCUO, FFXIV that are making strides into narrative and extensive voice acting, its hard for a game like WoW to compete with that given the choice is either rebuild the entire game from the ground up to include new features across the game, or limit new features to new zones per the new expansion. Usually it is the latter result. So the original limitations of the code act as an albatross slowing it down so other pastures look greener.
Basically, while of course improvements will be made over the years when you get down to it, any MMO will invariably only be as good as the potential the original release can allow. Its hard to take pride into the game you sink so much of your life into when you know people are playing games as advance technically as well as graphically akin to The Witcher 2 or ME3, when you know your RPG Looks like and has mechanics on par with Deus Ex 1
Just my take, take it for what its worth.
