First off, thanks a lot to RPG, Huayna Capac357 and rockinroger for volunteering to help. It will go a long way into helping us get 5.0 out the door sooner than later.
I also wanted to share a previously-unannounced change re: 5.0 (in partial effort to explain why everything is taking so long).
In addition to adding to several new civs and a couple dozen new leaders, I am re-aligning the North American native civs to be a bit more recognizable.
The Upaajut Empire will be split into the Inuit Empire and Dene Empire
The Anishnaabek Empire will be largely the same but will be called the Algonqian Empire
The Aniyonega Empire will be split into the Cherokee Empire and Seminole Empire
The Dinniheh Empire will be split into the Apache Empire and Navajo Empire
The Nimiipu Empire will become the Nez Perce Empire
The Piliwni Empire will become the Paiute Empire
The Tillikum Empire will become the Haida Empire
The Vooestaneoo Empire will move the Cheyenne to the Algonqian Empire, and will become the Metis Empire
The Iroquois, Sioux, Yanomami and Tupi Empires will remain unchanged. The Arawak Empire will be added.