Sorry to bust your bubble here, but there is no other side of Azeroth.
1. A Blizz Rep has already stated it a while back. I don't have the link but I do recall reading it.
2. There are holograms in Ulduar, Uldum, Mage quest from 4.2, etc, that depict Azeroth as a spherical planet. There is no other side in these holograms.
3. Blizz most likely won't pull the, "it was invisible" thing again, as they have used that for multiple occasions. Plus, we are talking about half of an entire planet here.
4. There is no lore even hinting at this.
As for the Emerald Dream thing:
Blizz did at one point have plans for the expansion, and data for it is in the game files. BUT... every problem regarding the Emerald Dream has wrapped up in books. Besides, all it would be is regular Azeroth all green and stuff.