why that? There had nothing left to progress didn't they? No world dragons spawning etc
I believe they left because their leadership was fed up with how shitty the server was. At that time it also had 300+ queues every evening, and people randomly DC'd every time, raiding was impossibly painful. And with no signs of improvements and/or AQ whatsoever, guild master and officers of Team Plague abandoned ship, and without organization the guild has been reduced to nothing.
As for world dragons, it's actually a very funny story. Dunno if it's true, I heard it from a human priest I met in Azshara. Basically, when the removal of Emerald Dragons was announced, almost every guild was eager to get a kill one last time. All those alliance guilds have been up, camping the dragons, not going to sleep, waiting as the spawn window was coming to its end. All guilds except Team Plague.
Soo... launch window closes. No spawns. All those frustrated, sleepless raiders unleash their wrath on forums, a huge flamewar erupts. Finally somebody asks TP members why the hell were they not around. The response: "GM announced that Dragons would not spawn for the last time". When asked why the fuck did they not tell any other guild, the answer was "We thought everybody knew".
Needless to say, nobody knew. Not a single lvl 60 outside TP has ever got told about it. So there you have it, completely fair, unbiased gameplay of Emerald Dream. I always knew that TP was basically the GM guild, but this shit made me lol so hard. Hope there won't be any bullshit like this here.