I really like the stone texture you've got going there.
Why have the windows like some sort of opaque shiny surface atall? Why not show what's behind them?
From looking at references it seems to me that the actual reflective properties of the windows on these buildings shouldn't be the only priority. Should help to break things up a bit and add a bit of interest.
It doesn't have to be too complicated, blinds, curtains or pictureframes for instance.
Apologies if you were planning on doing this anyway.