Axum is still a long time after Egypt and Nubia, though I agree that I'd prefer a later emperor, Zar'a Ya'qob in my case. The Bulgars were Turkic... I don't have to like it. China and Egypt need new leaders a lot more than Rome does, though. Like I said, I'd rather they be left out entirely than shoehorned into Rome. They were important and they were different and leaving them out feels wrong, but we are swimming in Greeks. If I have to choose between Byzantium and the Maya or Byzantium and Ethiopia or Byzantium and an interesting North American civ, it's a no-brainer for me to leave out Byzantium.