Actually I mean 8000 BC, because we have to remember that the Sahara was not a desert but instead grazing land, which soon turned more and more into desert. the point is first and foremost for historical reasons, and second I don't think Carthage needs a bit of a breather, in the sense that more workable tiles next to it could help Carthage (since desert tiles cannot be worked on), the same for Egypt where I still feel there is too much desert.
I can't think of anything of the top of my head, but the biggest one is probably snow capped Russia, I think more trees and ice/snow should be there and then later on (due to global warming) have the ice and snow be pushed up north and let more grazing land for Russian and Mongolian civs. Another one which I think is quite necessary is the need for more arable land in the Middle East, especially the Mesopotamian region, where did the "Fertile Crescent" go? Now you have the cities of Jerusalem and Sur/Tyre fighting for food when this was supposed to be the most agriculturally reach region. In fact I think that even when the Arabs are you should still have it but then half way through there empire maybe 1200 AD (something like that i'm not sure) you should have the arable land turn into desert, which would then lead to the steady decline of the Arabian Empire, which is VERY historically correct. I think the same for Europe but instead have a type of forest that you can't build improvements on (like RFC Europe) but then once you research a type of technology these forest tiles become workable, then leading Europe for there golden age.