Just Run out of ideas this is what I have at the moment, I dunno if in terms of composition is good or if I should add something.
Looks interesting. Is your final product going to be an image or a game environment? Do you have reference material you're working from? Maybe try adding some texture/color/light and then see what is still missing? It looks good so far.
Looks good to me, but you should definitely add an HDR image for lighting. It will make your scene look much better by default, even without materials.
It's a good start I think, I would indeed enhance a bit the lighting as well. Also, depends on what you intend to do with this asset, but I would add more details: I would add more windows on some walls. In terms of shading and composition look at some propaganda poster to get some inspiration, there's some good stuff to take !