Update 10 for SimCity is the one that'll finally, finally add the option to play the game offline and according to Maxis, it's in "final testing. Almost there Mayors."
This functionality was previously deemed impossible given the way SimCity was made, something you can't not poke fun at time and time again when talking about this subject. Moving away from always-online gameplay has been a six-month-plus endeavor, requiring reworks of "things that seem trivial, like the way that cities are saved and loaded."
If nothing else, the SimCity debacle has terrific potential for a case study.