Yeah, I don't know what happened. I couldn't view anything but the first page.
Dark, here is a screen of what I think a dungeon should be.
That took me about an hour to put together, including finding the textures on wadfather etc. I know this isn't an example of church architecture, but I think you were doing better there than in the dungeons themselves. See how I have some solid stone pillars and supporting beams that look as though they might actually hold something up? it really helps develop the sense that this is a real place and not just computer graphics. Obviously this scene is not perfect, but I think it's a good example of the LOD you should be trying for.
I've given it a wide aspect ratio so that it feels oppressive and cramped even though it is really quite spacious. This I think adds to the feeling of being underground. note also that the ceiling is rough, and looks as though a piece might fall and crush you any minute... (speaking of traps)
On further reflection I think my pillars are actually too slender. If i were to make this into an actual level, I'd want to revise them to have more of a massive presence.