My wishlist :
3D like City XL.
For highways & interchanges, sunken highways, bridges etc to be easier to build.
More landmarks & more choice of buildings. In SC4, it was annoying when the same buildings kept popping up in the city.
For zoning to be more like City XL. I didnt like the fact that in SC4 low density land value would become high & it would need to be upgraded. Real life cities have poor ghetto areas. A mixture of different zones would give the city a more realistic look. More varied buildings, so to create ghetto areas & affluent areas.
Buildings that dont automatically upgrade themselves. Buildings that remain the same, giving the game player more control over the look of the city. But also, if buildings dont change then the emphasis is on the gameplayer to carry out urban regenration of areas based on population demands etc.
In SC4, I found it difficult to maintain suburbs. If you upgraded low density to medium density, high rises would pop up. Cities with spraling low desnity suburbs & a central downtown core of skyscrappers.
Emphasis not only on building cities, but villages, rural farming communities etc. Also towns & cities that dont require all types of industries/commerce. Again this will impact the types of buildings you can develop in the city and the overall look.
Weather & change of seasons.
Natural disasters - flooding, droughts etc and their impact of communities within the city. e.g droughts leading to farm issues.
Econmonic depression.
Being able to download maps & street layouts from google earth onto the game would be awesome. So you can start a city with a road layout from a real life city & then fill it yourelf.
Differnt building styles like in SC3 e.g USA , European, Japanese etc.