Plain and Simple.
But however, it is kinda good!
You could improve it by removing Blizzard Cliffs - Or then you have to add some doodads & props to the cliffs.
Second one, You need a little bit more doodads & props.
I understanded that this is a Fiery Dungeon, which most likely means there can't be many grassy plants.
You can tho add Canopy Trees (From northend - Examble) and rocks (Dark ones to fit the theme).
Incase the doodads look too bright, try tinting them in the Object Editor.
Oh and, if you remove Blizzard Cliffs - Please make sure you will add Height Variations. Even tho they would hit already in here.
~ Regards
OffGraphic