Azshara's the clear winner here, so I've been working on the concept for a bit now. The writing and lore concepts for Rise of Azshara is pretty much done - now I'm in art-mode, aiming to put together a bunch of new character and creature designs. I'll put up a thread for it in a week or so.
This has come up as an objection before - it does seem counter-intuitive. Gameplay wise, I'd want an above-sea continent because, even though I was a fan of Vashj'ir, I don't want an entire expansion or undersea zones. Unless they changed movement so it was identical to above-ground movement, but I think that would just be too strange. Thematically though, I think there could still be valid arguments made - Azshara is arrogant/insane enough to think she can dominate the surface races, she's vain and wants to once again be queen under eternal starlight, etc. My story will have an additional reason, which is be unveiled over the course of the content.
Well, you never know your luck. Maybe we'll see the Emerald Dream in future, if not from Blizzard than from me.
It's funny, but my last concept project included a
trip to the moon. I liked it when they did the same thing in Wildstar - I agree it could be pretty interesting.
While I think you probably could roll both concepts into one, it would mean that neither concept gets to really demonstrate it's full potential. If the Dream becomes a single raid, we don't get an entire world to explore, and no dungeons and raids within that world. And too many Dream elements would crowd out Great Seas elements. I really think both concepts could support an entire expansion on their own, with a little creativity.