So what kind of gameplay expansions do you guys want to see?
Personally, I think it'd be cool if food became a commodity. Farms and crop farms produce foods to deliver to grocery stores, but you can import food from external connections for a price if you don't want to deal with rural components.
I've constantly wanted a Justice department too, to imprison cims and make crime a bigger role in the city, and parks should be much more diversified to include malls, theaters, museums (for educated cims), etc. This should correlate with age demographics, who need to be happy with their own unique placements (kids like parks, seniors like casinos, etc)
I think late-game cities would also benefit greatly from hotel districts, including casinos for tourists, which can also increase crime