They could have a great UA too:
Yugoslavia:
UA: Crimes against humanity - When cities start flipping due to unhappiness...
Oh yeah, I forgot how much Staline and Mao were an angels ... Certainly, I won't defend him for his crimes, because he really was a jerk. But at the moment Staline and Mao were added, I don't see a reason to add Tito. And in another side, he at least opened his borders to the western world. Of course, he is controversial, I won't deny it.
On the other hand, my wishlist would be :
Sumeria : First civilization (that we can call that way) known, "discovered" writing, first real empire ever known (some argue the first empire ever was the one of Sargon of Akkad, yet I disagree, as we can consider the first real empire being the one of Lugalzugesi). Sumerians had an extremely complexed civilizations, may it be :
1. on military side (developping the phalanx strategy)
2. the religious life (a gigantic pantheon which has nothing to envy from the greeks, and that the babylo-assyrians used)
3. and the social life (the bureaucratic system was very rich, and I won't talk about it here, it would be too long). Sumeria is a must for a game called "civilization".
I suggest the read of S. Kramer, History begins in Sumer.
Israel : Of course, I'm not talking about the modern Israel, but the ancient one. Israel gives us a religious power worth being mentionned, as its existence influenced the arts, the culture, and so on. Is there anyone in the world, or at least in the western world, who has not heard of Solomon, David, and their kingdom ? Certainly, Israel was nothong outstanding in the military side. However, Solomon was known for his series of contructions, and we could base Israel on that side (+ the religious of course).
Tibet : Once again, I'm not talking about the modern Tibet, but ancient Empire under Songtsen Gampo. And yes, I know people keep on saying it's hard because it's politically controversed, and blablabla ... But yet, ignoring that empire is an historical mistake (like the chinese official historical version when they say that the marriage between S. Gampo and the chinese princess Wenchang was an act of submission, which is totally ridiculous). Tibetans do not apparent themselves to chinese, and the only reason Mongolia is today a nation is thanks to the USSR which prohibited China to invade Mongolia since when the country adopted communism. However, if Mongolia was part of China today, would it be also controversial to add Genghis Khan with Mongolia ? The tibetan empire existed, it was a huge empire which welcomed ddifferent religions, like hinduism, buddhism and taoism.
Khmer : Khmer over Viet Nam, because achievement question, it was a lot more influential than the latter. And on top of that, Angkot Thom, capital of the Khmer under Jayavarman VII, was certainly the most populated city in the world during the XIIth century. They certainly influenced the most south-east Asia, and were genious engineers, being able to build an awesome series of canals, able to redistribute water in the entire capital, and surviving the long droughts of several months. Great engeneers, great artists, high population, great influence, damn it, what do you want more aside eurocentrism ?
Kongo : Well, there weren't many africans empires, and kongo was one of them, and a long lasting one. Unfortunately, although many would like to have Niga Mbandi as a leader, she wasn't. She was the leader of Ndongo and Matamba, which were rivals of Kongo ... However, we have Nzinga Nkuwu, who could fill the role as a leader. If I had to give a most important reason for Kongo, it would be his longlasting survival, and his intellegent relationshops with the western forces, particularly Portugal. And of coursse, it would add another african civ, and outside the Ghana/Mali zone, unlike the Ashanti.
Yugoslavia : Well, for every reasons I mentionned earlier, plus the fact tha twe would have a great modern civ to paly with.
