City Attempt: Iramir

[feanaaro]

This would be a major city in my world (see: http://www.cartographersguild.com/sh...illustrator%29 the city would probably be in the south of the large island in the north of the central "inner" sea).
It is my first attempt (again) so I am particularly open to suggestion and critique.
In particular I am concerned with:
- size: the city should be big for an ancient standard, but not enormous. More like Athens than Rome. Notice that the small buildings in the five "circles" are all 1-story houses, mono or bi-familiar, while the other houses are generally taller (2-4 floors) and more densely populated. Would you say that roughly 100thousand is appropriate (I still have to add some buildings, and other stuff around the city, like more trees, gardens, villas, cultivated fields, etc)
- streets-buildings ratio: most of the city has very narrow streets, because of population density, but perhaps I exceeded in that, what do you think?
- scale: at this resolution 2px = 1m (it is 1px=1m in my working file). Perhaps this makes most buildings too big, do you think I should say 3px=1m (1px=0,75m in my file).
- colours: I believe that most pre-modern cities have nearly every roof of the same colour, perhaps because they had limited access to different materials. Do you think I should conform to that? I used different colours because I wanted to emphasise the difference between the five "circles", the tower and the big central building (currently used as a big library/arcane university) which where built in an immemorial past by some kind of "precursors" http://tvtropes.org/pmwiki/pmwiki.php/Main/Precursors) and the rest of the city, which is more recent and more "mundane". But perhaps the difference would be obvious enough without using different hues.

Let me know.