The SimCity games I've played in the past rely too heavily on separated zoning and car traffic, often with broken transit AI (sims don't go backwards to reach a nearby transit stop) and no concept of walkability. While I don't think you should have to build your SimCity in a new urbanist style, it would be nice to make it an option.
I distinctly recall more than a few rail-only cities that flourished a lot better than any of my road-based or mixed-transportation cities ever did. Seemed vaguely unrealistic, until I realized what SimCity is actually about. At its heart, SimCity is about two things: 1) Acquiring residents; and 2) keeping the lives of those residents as comfortable and stress-free as possible. (Seriously -- the game would require you to take this to almost Wall-E levels of extremity).
- Roundabouts
- Traffic Circles
- Shared Spaces (no separation between road and sidewalk)
- Light Rail
- Street Cars
- High Speed Rail
- Bus Stops that didn't take up a whole block space
- People Movers (like the one in Miami, FL)
- Bike Lanes / Bike Paths
- Bridging neighborhoods together with sidewalks
- Walk-able Plazas that residents would actually use instead of being lazy
- Small 2 lane highways
- Bridge control
- Better street control so that every intersection doesn't force cars to stop and go.
And why on earth did they claim the Mono-Rail was the fastest public transit and best for intercity connectivity?! Monorails are notoriously slow and terrible for anything other than amusement park transportation.
My largest complaint regarding Sim City 4 was that the transportation add-on was almost essential to the game, yet it was an add-on, and cost extra.
Roundabouts are typically smaller (down to a mini-roundabout with an island just a metre or two across, compared with traffic circles which can be hundreds of metres in diameter). As a result, roundabout traffic typically moves slower, and they're MUCH safer.
The rigid separation of zones drove me nuts when I last played SimCity 4. Here in Vienna it's completely normal to have flats, shops and offices in every building. As far as I know this is even more extreme in Asian cities.
What I would love to see would be a triangle slider for zoning where you could for instance say this block should be 60% residential , 25% industrial and 15% commercial. Maybe some industries or commercial venues will require higher percentages to settle but this could also be an interesting tool.
My engineering ethics class covered a case in Houston, which has 0 zoning of any kind (or at least it did in the late 80's early 90's at the time of the events we covered. things might have changed) and the effects of putting a heavy metal incineration plant near government subsidized housing and elementary schools.