Reminds me of doom with hl textures. I'm pretty sure you are just sticking light entities in front of light textures when I think what you really want is this:
http://www.snarkpit.com/editing.php?page=tutorials&game=HL&id=53
Also if you browse thru the architecture tutorials you can find some that reno did on detailing your architecture as it is pretty flat and simple now. Seems like you have creativity, you just need to work on your application of it.