As concerns street illumination... actually there are no light at all (in real place). To give it some light I thought about something like UFO with lights over the scene... I don't know yet...
And of course it is necessary to add a lot of construction junk to the map, you are absolutely right! It makes the scene looking natural and gives people places to hide from bullets.
I'll think about adding a custom music track to it but I'm a total NUB in it

As for export time, I didn't measure it precisely but I think my computer do it in roughly 15 - 20 seconds (Core 2 Duo processor, 2.4GHz frequency, 2Gb DDR2 800 MHz memory).
Rad Ished Yes! You are absolutely right! I plan adding some construction parts into the map. Original place contains a lot of rusty armature, cement boards, column elements, one broken crane and even underground tunnels (unfinished accelerated particles collider)

Thank you all for very helpful remarks!