I don't think they'd remove something that everyone in the game went to take screenshots with at one time or another... at least I don't think they would. That concept art with a destroyed Isghgard-looking thing makes me nervous, but the new bestiary entries say the wyverns are on the front lines attacking them so I guess the city is still there.

I wonder if they built that Rapture bar I tried to rally for! (lol)