We got 6 new civs with warlords. I'd expect to get a few less, but more leaders on the other hand. The musts:
Babylon, it's the biggest argument for the second expansion...
A
North American Civ, be it Mayans, Iroquois or Sioux, they've been an Civ All-Star, they will be in!
Possibilities of which a few will be chosen:
European civ I: We're talking of the Netherlands and Portugal on one side, and of Poland and Hungary on the other, both representing two parts of Europe ("colonial" and slavic), another idea would be incorporating Hungary with Austria to include Empress Sissy ...

because Austria alone would just be too "German". In each case, these civs could be used well for either a Napoleonic or a WWI scenario.
European Civ II: Europe deserves at most two new civs, which one can be battled out between themselves.
Southeastasia: the big fat blank area to this date in civ. I would have put it into the musts if Firaxis hadn't have left it out for the first 3 civ games. Candidates are Thailand, Khmer, Vietnamese, Indonesians in order of their respective likeliness imho. The Tibetans would also be an interesting addition, but I doubt it due to China.
Mesopotamia II: Babylon has always been a representative for all of the region, but I nevertheless wouldn't mind Assyria, the Hittites, Sumer or Phoenicia (again in order of their likeliness imho).
Africa III: This is a big doubt, but perhaps they'll include Eastern Africa.
Native America IV: Again, if they include Iroquois/Mayans, they could include the other as well.
Counting, I have 2 musts + up to 6 possibilites. therefore I think we can count with 5 new civs, but with some more leaders. First, there's the priority of filling up the one-leader civs:
Greece II nuff said, Pericles or whoever to give the Greek civ a "builder face".
Persia II dito
Spain II There absolutely has to be a non-crazy Spaniard.
Japan II There must be a way for Japan to not be isolationist.
Tukey II Don't they deserve?
Arabia II erm, yes, I've had to put them onto the list
After that, one could give a second leader to (in order) the Korea, the Vikings, Inca, the Celts, Carthage, the Aztecs, Mali, Zulu. But most of those do not seem necessary, I prefer some great statesmen of the real big civs that already have two leaders (
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Rome: Trajan,
Hadrian, Scipio, Marcus Aurelius
America: "Good Ol' Abe"
Abraham Lincoln seems to be the only undisputed choice
Egypt: Thutmosis II. (or was it III. - the expansive one),
Cleopatra
Germany: Fredrick II. von Stauffen or
Barbarossa
China: I know too less of china
France: From de Gaulle to Jeanne D'Arc (old civ3 joke

)
Charlemagne will probably be left out to the dispute with Germany...

India: I can't name one specifically, but there are many noteworthy
Mongols: no
England: already got 3 leaders which show most of it
Russia: Ivan the terrible as fourth leader? no thanks.
that'd result in 8-11 new leaders, more than enough (warlords had 4!). Add in the fact that Babylon could receive two leaders (and instead no Mesopotamia II), and you get the image that there will be practically no new leaders, but another expansion pack ...
mitsho