Man, this is all great stuff. I really like the new graphics, they look great. I really like the stone houses with the central courtyard. The mode switches do look out of place, but I'm sure those are just place holders for the mock up. Great job Shawn!
I really like the mesopotamia map idea. Maybe you could have a choice for the level of green. That way you could focus development to be near the rivers, with desert starting some rough distance away from the water. You could also apply some debuff when operating on desert terrain to inhibit travelling or developing much away from wet regions. Maybe dot the deserts with oases or whatever.
Anyway, I love it. Can't wait to try it out.