Unfortunately, what seems to be getting reported on (and popular opinion) is different e.g. here http://www.rockpapershotgun.com/2013/03/12/simcity-server-not-necessary/
Also unfortunately, there are now some criticisms being reported about the simulation/gameplay itself: e.g. here http://kotaku.com/5990362/with-simple-ai-like-this-why-does-simcity-need-cloud-computing
However, since I have not played the game I cannot opine how badly the latter would affect the fun level, if at all.
Hm. Was Sim City 4 like this? I remember following a sim to an specific house instead of just the first available one, I might be wrong though...