I've been making a world map for my own mod, with many modifications based off of this map. The base map is Rhye's Earth map, BTW, and it's not anywhere near finished.
Hawaii + California
Hawaii is now very much habitable, while Yelamu can easily grow to become a large city.
Improved Alaska
Alaxsxaq is now atleast somewhat worth taking (I'll eventually add some closer to the city.)
Improved CONUS and Canada
Lots of new resources! Also, the USA is replaced with the Delaware Pacers

p), who start with two cities.
Mexico and Central America
Aztecs are replaced with Hidalgo's Mexico. They too start with 2 cities. The Mayans can be a problem, but aren't too big a deal. Note Cueva-Yaviza starts Incan now.
South America
Only real differences here are Incan Cueva-Yaviza and the fact that Incans from Qusqu can easily reinforce Cueva-Yaviza. They were the first civ in the Americas to have a 2-city start, and it helps a lot - in one game, they were on technical parity with Mali, Britain, and India!
South Africa
Basically the same, really.
Egypt + Ethiopia
Aksum is present instead of Djibouti - bigger threat/deterrent to an early Scramble for Africa. I haven't gotten to Arabia yet, though.
West Africa
The big changes are nerfed Carthaginian barbs, one barb city in Morroco instead of two, and Koumbi Saleh, fresh from Earth 1000AD.
Western Europe
Simply shows the changes Rhye did to Europe. Spain is occasionally a major player in my games now, while in my most recent game, Rome was one of the most advanced civs!
Scandinavia
Big changes here - much larger and more accurate than the basegame's version. Most of the changes are based off
this post.