See, okay but here's the thing about this comment and the comments below. The Emerald Dream is inherently tied to Azeroth past. It is the path of what could have been -- if the Legion had not invaded, if there had not been a sundering. The Emerald Dream as stated on wowwiki: "It appears to those who travel within it as Azeroth would have appeared without the development of the sapient races, which means that it is what Azeroth would have been if not for humans, elves, and other intelligent creatures. In essence, this plane shows travelers what their world would be if intelligent races had not cut forests, farmed prairies, diverted rivers and built cities (and had Kalimdor not been shattered by the Sundering)."

The question is when did the emerald dream start going bad? When the Titans first chained Old Gods underneath Azeroth or at some later point due to the influence of sapient races. Like maybe during the sundering there was an effect on the Emerald Dream that was unexpected or something along those lines.