Something tells me people haven't forgotten about SimCity's notorious online debacle. That something's name? Cities: Skylines, which will also allow for extensive modding and "massive" cities.
The "play offline" bit comes toward the end of the video (worth noting: SimCity can now be played offline as well; it's still not very good), but that's hardly the only reason this one is worth paying attention to:
"Developed by Colossal Order, the simulation virtuosos behind the Cities in Motion series, Cities: Skylines pulls players out of the public transportation offices and grants them the power of true urban planning and development. From zoning to building, from utilities to beautification, and from taxation to outreach, players of Cities: Skylines will have total control in endless sandbox gameplay across massive maps -- all with extensive built-in mod support."
Those things certainly sound nice, and the game's colossal anthill empires look quite impressive too. The people making this aren't exactly being subtle: "Remember SimCity?" they may as well be saying. "Remember how it crushed your dreams and then raked their remains across a Slip 'N' Slide of shattered glass? Well we're gonna do... not that!"
That said, the Cities in Motion games have a reputation for being exceedingly complex and a bit rough around the edges. Hopefully Skylines will strike a solid balance between ambitious depth and sun-dappled polish, but that's still up in the air right now.
Cities: Skylines will be out next year.