How so? They've added a couple of things and changed the loot system for LFR. I wouldn't call that a drastical change. Normal and Heroic modes are unaffected by that. Basically what they did was give players something to do outside of raids, because players complained there was nothing to do outside of raids. Now they complain that they have to put in more effort to get maximum rewards. It's really weird.
They've recently recovered about a million subscribers. However that has nothing to do with the argument that there is nothing to do in the game.
That I feel seems to be the biggest problem.
And what direction did they go? Like I said the core is still the same. If you played WoW til now because of raids, you can still do them. If you played WoW because of quests, you can still do them. In every expansion there are people saying "This game has gone into a direction I don't like so I'm gonna quit"
The only thing I can see different in MoP is that, for reputations you don't sling on a tabard and grind heroics, you get interesting content. If you don't like it don't do it. But then don't complain about the lack of content.