More than half of the civs in Age of Kings were non-European. Yes, you could argue there was more European influences on unit lines and so on, because guess what - the devs created the game based on pop history knowledge of the audience. And even with that in mind, the game still managed to go outside of Medieval Europe for its time, and continued to do so throughout the expansions.
Okay? So your claims about Africa being just tribes is… well, unfounded. Or is Russia an African tribe for you, that you’re somehow an expert on it?
Honestly, the recent influx of Russian/slavic nationalism on the forums has smelled really weird, not gonna lie. I truly hope the devs don’t actually look at whatever’s posted on the forums as ‘oh the people REALLY seem to want a Balkan or Slavic DLC!’ just because five accounts have spammed threads about Slavs in last week.
Once we get to a Slavic DLC after 3-4 DLCs outside of Europe we can name it ‘Age of Tribes’ and get your slavic tribes like Albanians or Serbians or whatever else added to the game, sure.