We know that the cities aren't changing much at all, and everything will remain largely as it is.
However, since the GC's play a major role in storylines and character progression, I would like to see them have their own buildings (at least from the outside)
This wouldn't be extremely difficult to do either as it would largely be a cosmetic addition to the edge of the current GC/Market Ward zone.
I put together some quick sketches for how they could look.
As I said, its a cosmetic build on the other side of the current CG/MW zone (and there are plenty of existing assets that could be re-used to build them). Because of this, the resources vs the rewards for implementing something like this are quite reasonable.
I think many players would find that a simple addition like this would help flesh out the cities and provide visual significance to both the Wards and the Grand Company HQs in 2.0.
EDIT: Added Ul'dah wards