I don't like the terrain.
First of all, the doodads don't blend in with the ground texture, and the lighting feels wrong all together.
Also, it lacks depth.
First thing you do, change that fog to something blueish, like
this.
Second, experiment with the lighting sets to see if you can find one that fits nicely. Seeing how isengard is undermined by fiery chasms, you might want to test the dungeon lighting set, but it could also look awful due to the extreme colour changes it does to the doodads. Otherwise, just try to find something blue and gloomy.
Second, change the tiles. i think dalaran ruins rough dirt is an excellent dirt texture, maybe it will fit. Just don't use any tiles with too sharp edges, and if they do have those, make sure the tile is low in the hierarchy. Again, you should choose blueish tiles that look very dead.
third, make the chasms deeper. if you haven't got miscdata.txt, get it. Then you download some of the large rock models from xgm. Choose the ones which are 90 degrees tilted, e.g. standing, and use them to cover the walls of the chasm (you can check out some of oGre_'s or Lexantritte's terrains to see how it is done).
Finally, download the "UnrealTree" model pack from XGM. They look like basic trees with billboarded leaves on them, and are very useful for this. Use the Felwood or Cityscape variations and use them for all the vegetation outside the walls. The contrast is supposed to be evident - outside, the forest is still alive and green, while inside the wall, it is all scorched. For the trees inside the wall, use the dead tree models from the UTM (the ones that uses the icecrown tree textures).
Good luck!