We're almost half a year into the Firelands which is still bugged, heroic version is nowhere to be seen (later with that) and don't get me started with T11. Bugtracker is full of issues about all three raids and no one is even bothering to say anything, which is sad. It feels like you have abandoned the server, or well that's how I feel. I have to lead 25 players three days a week and I don't even know what to raid as wherever we go something is broken. I don't know what to tell them where we're supposed to go next, as there's nothing to raid because of the bugs.
There are only a handful of bosses which are working good but others are like either broken or laughable. I know that now it's a last tier but since we have no Firelands heroic there's nothing else to do. People are leaving the server because of that, that's a fact. You could say that people come and go, that's true, but in the last two months about 10 people from my guild quit the game because they just couldn't stand afk key smashing in Firelands.