Since we've officially revealed that Ethiopia has a unique improvement, and not a Holy Site, I'm wondering what other possible infrastructure the new Civs can have?
Here's a list of buildings that don't have a replacement yet and what I think could possibly go there, or at least the ones I think are most likely to get a replacement.
Monument: We don't need one. We have the Old God Obelisk.
Shrine: I feel like some Civ will get one but I'm not sure who. Vietnam has an interesting history most of their population today still holds on to traditional folk religion so a shrine replacement representing that might not be out of the realm of possibility, however at the same time the Water Puppet Theater sounds like it might work better as an improvement. I'll throw in Burma as a possibility as well.
Library: I think Babylon or Assyria could get this. Babylon is a science city-state already and it would flow right into it's suzerain ability with it being able to hold a Great Work of Writing Slot. Assyria could easily get it to even as a Leader infrastructure for Ashurbanipal.
Workshop: My preference if we could get a unique workshop could go to Italy. It could grant culture and extra writer, artist, and musician points in addition to the abilites of a regular workshop.
Granary: Longhouse for Iroquois would work or even a Ceremonial Hogan for the Navajo instead of making it an improvement.
Lighthouse/Shipyard/Seaport?: After two unique harbor replacements I'm not sure if this will happen. The civs that could have possibly gotten a unique lighthouse has past I think. Portugal could get a shipyard but I expect them to get a Feitoria in the form of an improvement.
Art Museum/Archaeological Museum: I don't see this one happening unless Italy above could get some sort of third option that could hold both? Though I don't associate Italy with archaeology.
Armory: Assyria was known for building some of the first arsenals/armories in the world so this could be an option. This would synergize with their Ancient Era military engineering skills as well.
As for districts I think there's a possibility we might get one more unique district as the past 2 expansions we've had 2. Considering the Campus and Harbor has 2 already I won't do a prediction for them as well. Nor the Water Park, Govt. Plaza, Dam, Canal or Diplo Quarter because they are in expansions/DLC. Also Spaceport and Aerodrome for reasons.
Holy Site: Since Ethiopia didn't get it I'll throw out Burma as a possibility again. I could see the Byzantines, but I'd rather them not get one as it would be too similar to the Russia Lavra.
Encampment: If Assyria doesn't get a unique armory, I don't see why not they could get a unique Encampment. I'll also throw out maybe a Kasbah for Berbers/Morocco.
Theater Square: Water Puppet Theater could be a district in itself but I'm not so sure on this one.
Commercial Hub: We just got a unique one in GS so I'm not expecting another already though if Siam does make a return the Floating Market would make a good district. Other option could be Portugal but I've said my reason above.
Entertainment Complex: Hippodrome for the Byzantines would be interesting but I can also easily see it as an improvement or building.
Industrial Zone: Unless they want to do the Feitoria as a coastal Industrial Zone, but I don't think so.
Aqueduct: Assyria again? Probably not.
Neighborhood: Not expecting another unique neighborhood but it could refer to a Medina Quarter for Berbers/Morocco again.
I'm not sure they would reveal it so soon, though. Ethiopia, Maya, and Gran Colombia have all been fairly heavily requested. They seem to be the hook into the pack, with the rest being more pleasant surprises. Someone said a few pages ago that Genghis and Suleiman would have been enough to sell their respective expansions, and I think Maya, Ethiopia and GC are what NFP is getting for that. The rest of the content might just be a hidden icing on top.
I know probably they won't. That doesn't mean I don't want them to.