Originally Posted by
gamma Ray
The Old Gods and the Curse of the Flesh are older than the well of eternity. According to the WC3 manual at least. The Old Gods and their Elemental lords ruled over Azeroth which was in utter chaos. After the Elemental Lords were banished to the Elemental Plane and the Old Gods chained within the earth, natural calmed and Azeroth could be shaped. During this time the Dragons were given their task along with the Earthen, Sea Giants, and other Titanic creations. The Well of Eternity was created after the Old Gods were defeated, meaning that the Curse of the Flesh was before the titans came or the well.
As for the Old God speculation.
R'lyeh is an underwater city that Cthulhu lives. In the Lovecraft story "Call of the Cthulhu" and "Dagon" the "city" is simply an underwater island that raises out of the ground that the characters visit or hear about.
Blizzard loves Lovecraft so much (and who doesn't!?) we can guess that Ny'alotha is going to be an underwater land that rises above ground. I would expect it to be near or within Vashjr.
The Emerald Dream is just that, A dream. The entrance for players are the 4 portals in game, but for the druids they sleep. Their pact with Ysera was that they would sleep for allotted time and live in the dream and then come out and live in the normal world for a time. The World Tree is not a gateway or has been indicated as such by any lore that I've read.