I think your warm lighting is too intense for a lantern, and the shadows are too dense. Overcast skies are diffuse and would bounce light into those black patches. Looking good.
So, what about the specular/normal maps? Are you using a semi-automated process, with Substance or similar, or are you creating a heightmap from the diffuse, displacing a mesh in ZBrush and then polypainting?
one thing you could try is tiling the normal map but only tiling the diffuse horizontally, that would give you a degree of detail while allowing nice colour variations
Some general wear and tear can be added (although I'm guessing you'll be doing that since you mentioned the diffuse is still being worked on.) The face and modeling in general rocks :)
The stones in the wall are to clean. Because the surface is 1-2 cm above the stones so you need edges and shadows, influence not only the diffuse map and make a bumpmap too.
A good tutorial on this workflow: The Desert(What can you do with no diffuse maps?) More tutorials and guides on the MultiTexture wiki page, also check out the Texture Atlas page.
By a simple base color do you mean a texture or the diffuse color of the material? I understand that you worked mainly with textures, didn't you? Thank you for your reply.
Update with textures I'll refine the model in the future, for now since deadline draw near I just have to texture this for now. UDK shot Max Render: Diffuse Spec
Here's an update on the basically finalised model. I'm also playing around with the base diffuse colour assignment, but I'll be moving onto the creep den next before UV and texturing.
Oaky, so my final point of confusion. What goes in RGB? Does it just show a multiply of all the layers beneath it, or am I supposed to put my diffuse there?