Not considering the servers issues the game itself is fundamentally broken with no control of saving and erasing cities.

User Rating: 2 | SimCity PC
Here is the scenario:
In a region, you have 4 cities. They must work together to build a Great Work. One city save file gets corrupted beyond repairs (because of being forced to save online), another city gets obliterated by a nuclear explosion that never goes away and render the city inhabitable, and a third city has all it's land on a plateau which can never be reached from the highway down below. So you are left with one city to built the Great Work on its own as the others cannot be erased, repaired or terraformed. Great... And I didn't even have to talk about server issues, always online, etc...

So until we are able to either delete a city, save the file locally so we can revert back, or being sure that saving online isn't going corrupt the save file, it's not a worthwhile investment of your time to create four cities to have them get broken.