I also thought on Balkan civ's Carthographer. But as they are relatively weak in they military and with the exception of Serbians don't shine defending themselves, I think a civ like Russia is a better Nemesis. Ethiopia doesn't actually excel at military in teh early game and even if their towers can becoma into a nightmare, they will only have enough after quita a bunch of game-time. Also, as Egypt lacks buildings, if you handle fine with tactics you can turn their artillery power useless.
About Praguay....they deserve a better nemesis