This is really great varwnos.
It is crowded, but I like it. A few suggestions, though. The crosses that face to the right seem too large, the ones to the left, however, look good and more proportional to the scale. The new rotunda church looks ok but the contrast seems to be different from the rest of the city - the shadows don't look dark enough. And the last thing is, a lot of peole comment about your rooftop color, I agree that they look a little flat and monotone. If they were a litle more realistic and less cartoon-like.
All in all though I think these will look great for the Medieval Byzantine region.
P.S. - I've never been to your city, and so I've never seen the St. Demetrios basilica before. I had no idea that anything that nice still existed. Nice.