Obviously there is so much we don't know, but a big question i have has since unstacked cities were announced is still unanswered.
How will unstacked cities affect island cities, and how feasible will really small islands (1-4) tiles be for a city? Will those cities just have to be very specialized? Are there any water tile districts besides harbor?
I think they said there will be less water and bigger maps to make really small islands not that common. Some wonders need to be built in coastal water, too.