Exactly, you finally got why SSGI is not enough and extra occlusion is needed to complement it, being it sky shadow or AO. Performance impact or not, SSGI is not sufficient, as you have finaly understood (I hope).
Windows are made out of mirror, because, as I said, this is representative of a future development, the levels are empty. If you are judging by the windows you are doing it wrong.
There is no room for improvement in the building materials because they are already correct. If baked it looks right, with Sky shadows or AO it also looks right… They are also following the guidelines from epic when it comes to albedo, specularity and so on. It’s all good.
Mapping is also correct, as this is generic and not specific.
Wrong again, AO and GI are the issues, nothing else, as the baked scene looks fine, and SSGI + RT Shaodws also look fine (but costly), the problem is that I dont want to bake the scene, at least not using lightmaps for the buildings, that does not fit the workflow for this project, the sun needs to be dynamic and its best to not waste too much time unwrapping buildings as they are subject to change all the time.
Realism is also not the desired outcome, it has to look good for its purpose, not real.
If I was after realism I wouldnt be discussing SSGI, AO, RT Shadows and what not, I would bake the scene.