AbsintheRed
Deity
As an Australia, I do not like the idea of Australia being included. We still have the Queen as our head of state and the Union Jack in the canton of our flag, I mean, we aren't all that distinct from Great Britain even now. The United States is very different in that they have had a very long time since their independence (and they are truly independent) to forge their own history and identity, and we are still in the process of building ours.
As for Civs, consider who we had for the last expansion pack, which was based around religion and the various time periods were religion played a huge role:
Austria - Leader from 18th century
Byzantium - Leader from 6th century
Carthage - Leader from... not entirely sure, if I recall she was supposed to be the founder of Carthage, which would make it around the 8th century BCE
The Celts - Leader from 1st century
Ethiopia - Leader from 20th century
The Huns - Leader from 5th century
The Mayans - Leader from the 7th century
Netherlands - Leader from 16th century (if I recall correctly)
Spain - Leader from 15th century
Sweden - Leader from 17th century
So there is a flavour towards some religious leaders and civilizations, but ultimately there is a lot of wiggle room in that seemingly. I think we'll see some Civilizations that are based around the "One World" concept, which I'd guess is to do with the modern age, colonisation and globalisation (please, please fix diplomatic Victories!), but ultimately there will always be a few surprises.
In terms of the concept though, the Zulu will almost certainly be in. Along side colonisation is the what went on with local groups, and the Zulu are the perfect one for them. You can pretty much pen that one in already.
I also doubt that they'd go for too many "modern nations" as it just doesn't really fit. Brazil is a maybe, but ultimately in Civilization games they generally don't put modern nations in unless they are of the likes of the United States. In terms of colonisation though I'd expect Indonesia to also be in. Personally I'd think they'd put in Sumeria as well, and would like to see the Moors and a return of the Khmer, but they all move away from that concept of "One World" seemingly. Phoenicians might be a shout due to their colonisation of various areas, but I doubt that one.
Based on Gods & Kings I think we can expect about 9 new civilizations and one other included, one which is currently DLC that would fit with Colonisation or the modern age. Maybe Polynesia?
We'll also probably see a second native North American group in the game, although I'm not a fan of over representing the region simply because of the origin of the game, but hey... that's what's likely to happen. To me at least, the Olmec and Zapotec would make more interesting and more relevant inclusions if you were to go down the path of more Native civilizations from the Americas, but the groups of what is now the US and Canada generally get more representation and it will likely be the Sioux based on previous inclusions. Nothing wrong with that of course.
So long story short, I'd expect to see:
The Zulu
The Sioux
Portugal
I think it's likely we'll see:
Indonesia or equivalent
...and there's a good chance there will be:
Sumeria
Phoenicia
I'd also love to see:
The Khmer
The Moors
Mali - yes I know that some will say that we already have the Songhai, but they are different
Whilst others have suggested:
Poland
Kongo
Brazil
There will most likely be 10 civs with one already as a DLC, I'd guess Polynesia, but it's just as likely that it'd be the Inca, although I get the feeling that they gave people Spain so the more concern with completeness would still need to buy that DLC, but maybe I'm just cynical.
As for announcement and release date, as I've been saying for a while now, it'll most likely be announced on a Thursday based on previous announcements, at a guess the 14th or 21st of February, with the 21st more likely as I doubt that they'd announce it on Valentine's day, although you never know. If it is indeed a mid to late February announcement I'd expect it to be released in June, if it's announced in March instead, it would be for a July release.
I absolutely agree with your thoughts
Btw, the civs you choose are all doing great in the civ poll: http://forums.civfanatics.com/showthread.php?t=460009
You only missed the Hittites, Hungary and Tibet from the most popular ones
EDIT: new link to the poll itself