Ah yes, that thing. I believe @Synaesthesia made it a decade ago for Renegade in one of his levels.
As for your screenshots, I can tell you that you have more breathing room than you may believe you have. You can - and should, given a building like this is a center of attention - absolutely add more props and technical elements to it. Providing you don't go overboard on unique meshes of course, but that you already know!
You can also improve the texture scaling a lot more, a number of your textures are very stretched (see the ceiling trim and walkways). You might want to avoid using Renegade textures as well due to their low resolutions and general easy of recognition. Additionally, don't be scared about adding additional detail work with the textures. I personally enjoy doing that and always get a little carried away with it, often also creating new textures for specific parts. As for the exterior, you ran into the same problem I had with Siege's castle wall; Making large man-made objects not appear extremely tiled, and the only solution is increased texture variation and UVW usage (and some other means to break the line of sight, I personally used scaffolding supports and trees for this on Siege).
The domes could also be replaced from a low poly sphere with a texture, to an actual 3D frame with glass in between. Given that this is a prominent part of your building, it helps to put that extra work into it, it'll look a lot better for it (plus you only have to do the model once and then copy it two additional times, how's that for cost efficient development!).
Finally, the use of lighting is not proper. You need to draw the wireframe in order to draw the shadows, and you're probably using a too large light preset and will need a custom sized one for that room (you're probably using the light post one). I cannot tell you any more without seeing the actual wireframe, but the floor has too few polygons at least, plus the sole verticy is obstructed from being solved in a desirable way.
I've had a lot of experience working on man-made objects in my APB contributions, trust me when I say, to get everything right on W3D you need quite a bit of patience (the Advanced Naval Yard and Siege castle walls took a fair while for example).