Very nice, I really like the atmosphere, but I dont think it fits for Isengard.
If you're trying to make it look like in the movie it need lots of lava(smelted iron) and industry(working orcs and stuff, maybe a heavy smoke also)
I dont know what this is for, but if its for a cin or something that uses these camera angles, i suggest you import new columns for the ones in the third picture, they have some polygons deleted on the bottom to reduce polycount, wich leaves some ugly holes when vieuwed from that angle.