They are, but leaving the description at "parts of the game logic" could be taken to mean the servers are being used to offload compute-intensive tasks. Centralization for the sake of performance is understandable, but not allowing offline saves sounds more like centralization for the sake of centralization.
I think that the regional city interactions and global market count as 'parts of the logic'. I agree it's not compute intensive, but it is fairly central to the design of the new SimCity. No reason the region couldn't be locally simulated IMO, however.
That is ALL.