As I've said before, I haven't read every post in the 24 pages of this thread, but I've skimmed through them and got a general idea of the kind of things people are saying.
Most of the focus seems to be on the tactical side of things, ie how you will attack an enemy city, move your units to face the enemy, which units will be good against which other units, etc.
But what about the strategic aspect, eg how you will design your army for attack or defence, which units will you build in which cities, the limited availability of resources, and the tech path you will take to get the units.
Obviously a lot of this can't be answered until we know more about the game, but there are a few things we can speculate about (even if we end up being wrong.) For example;
Military cities: in Civ IV, it is common strategy to have one (or more) military cities that build barracks, military national wonders, hammer multipliers, and then do little other than pump out troops. Will this still be a valid strategy in Civ V? What will your military cities do when you reach the limit of the number of troops you can support? (either through limited resources, limited space due to 1upt, or excessive upkeep costs)
Early Rushes: We know that a city can only be defended by one unit. Will this make the early rush even more powerful, especially if fast units can bypass any defenders that have to leave the city? Or will the fact that cities have hit points mean that an early rush is doomed to failure because it would take too long to capture the city?
Cultural Borders: If you conquer a city that is inside enemy cultural borders (or on the coast of an enemy landmass), , and then make peace, leaving that city surrounded by enemy culture, or have a city that is coming under severe cultural pressure, how will you defend it? If you don't have open borders with them you won't be able to put units around the city, so will it even be worth trying to defend these cities?