Looks pretty plain to be honest. I mean, the actual terrain itself. The fog and effects are nice and give it a tense yet calm atmosphere, but the terrain looks unfinished IMO. There could've been more trees and environmental doodads such as rocks on the elevated land mass which the Deathknight is standing on is basically what I'm trying to say. And the area where its cloudy... it sort of looks messy. Those hills in the cloudy area were probably meant to look like the tops of mountains peaking out like in the movie "Emperors New Groove" but the 'mountains' you made are too small and should be pointier and slightly taller maybe.
When you first look at this image, it looks nice but blares out and isn't very eye-friendly as the purple burns my eye sockets. So it looks nice anyway though. But once you spend time studying it, you notice its flaws pretty easily and what's missing.
~Craka_J