I'd also like to see some more Mezo-American civilizations, more Asiatic civilizations (Something east of Iran, west of India would be nice. But I don't know if Afghanistan or Pakistan sound Civilization-ish enough, I'd prefer something more deeply rooted in history, not recent states. I'm sure someone might know the Ancient histories of this region better than I).
Timurids!
actually, I believe for the most part that region was dominated by Scythia, Persian Dynastys, Mongolia, and Indian Dynasty's in addition to the Timurids.
for what its worth, the Timurids are 1 of 4-5 Civs I would add in, if I were going to make a small "non-themed" expansion. By that I mean, just a general group. I say this because one could group just about every civ mentioned in this thread into "groups" that are generally defined by the same restrictions. For example
A) Nation American/Pacific Islander: Iroquois, Sioux, Cherokee, Polynesia, etc...
To me these are all the "Tribes" that never built "great empires" and very little history is known about. Some I wouldnt have a problem with, but to me they would all be very similar.
B) Poland/Austria/Austria-Hungary/Scotland, i.e. European. With the exception of Poland, the others seem to be "represented", all-be-it, incorrectly, by an existing civ. HRE to me represents Austria, and I know that comment will cause a massive argument, but to me Austria's hayday, also existed as part of the HRE. (the Haspbergs). the A-H empire was just a continuation of that after an alliance between Austria/Hungary. Likewise, Scotland is represented by England.
C) Ancient Mesopitampia: Hittitte, Judea/Israel, Assyria, Thrace, etc...
again, I wouldn't mind any of them, the Hittitte's invented Chariotry, Assyrians developed the basis behind Siege Warfare, but again that argument can be given to any group "so and so invented _____"
D) SE Asia: Siam/Thiland, Vietnam, or what have you. This region has always been underrepresented in Civ, and I am happy that Khmer and Korea finally made it into Civ these last 2 editions. Again I wouldnt mind any of them.
I didn't want to get into a rant, but I did.
To me one can put an argument up there for any of the mentioned nations (in addition to the 34 represented in Civ4) The fact that one isn't in doesn't give any disrespect to that group, There has to be limits. I mean, the UU and UB don't seem to be that different to me, and without another Trait, the leader's would just duplicate traits. In the end, the game is Modable, so just add who you want.
Anyway, I know I mentioned them before but my "list" would be:
1) Timurids
2) Poland
3) Judea/Israel
4) Iroquois (Remove Native American Civ)
5) Sioux (Remove Native American Civ)