There's potential but it isn't there yet
The biggest problem so far is the forced online mode. There is no option of playing offline. Personally I don't really play with friends online (just not my thing ok) so having to play online is not my thing. I just want to go in, experiment with cities, and play. The fact is so far EA does not have enough servers to meet the demand and if you are lucky enough to find an open server after quitting, it may not be the same server you were on earlier; leading to two annoying problems if you don't already have a city on that server. The first is that you have to replay, or at least endure having to load up and then quit, a tutorial (something which is useful for completely new players but useless after you've been through it once). The second is if you can't go back to the city you spent hours working on. You have to start from scratch.
Yes, EA wanted to make this a social experience but like Farmville (or any of its derivatives) you should be able to play on your own. You shouldn't be forced to interact with people if you don't want to. You shoudl be able to manage multiple cities and watch them grow as you set fit.
Aside from that, the game is all right. There is potential for a player to be quite creative, it just takes a bit of time to be able to do what you want.