While it focused more on a Central/Southern Africa themed game, you could look over Nyambe.

http://www.atlas-games.com/nyambe/

Otherwise, you run into much the same problem as any non high fantasy D&D game: heavy armor is useless, spellcasters are even more powerful, most other settings don't have the christmas tree effect of modern fantasty, etc. There's plenty of threads with ideas on how to deal with that though.

Setting wise, might be fun to point out that this empire is the latest in a series of similar empires with different ethnic groups in charge (which why even random villages could be very cosmopolitan in population and religion).

Personally, I think religion could be really interesting here. You can a very accepting monofaith like Islam, and a random bag mix of traders gods, whatever they worshipped before, and be great fun. Consider: Thor, Anasazi and Jesus walk into a bar...

Cool idea, hope it goes well!