It seems that most things i'm interested in seeing changing are already listed here.
We all know traffic is broken, whoever fixes this is a god.
We all complain about city size, i know that it might not be possible but i'm sure people are working on it.
One way streets would be pretty good.
A revival of the old Simcity challenges/opportunities would be nice. Build a Jail/Nuclear waste dump etc. Money vs pollution.
A big one for me, would be region road connectors. One on every edge would be nice.
Perhaps an entire region that is perfectly flat? To allow us to cram more into one city.
The ability to designate exactly what type of buildings are built would be nice, i know we can do this by altering road density and taxes etc, but it'd be cool if we could deliberately create a downtown area where it's only low wealth.
I'd love to see some of the sandbox features made simpler. For example, the 'cheat codes' which turn fire etc on and off made into their own tab and simple check boxes.
Perhaps a larger loan/bond amount. quarter of a million maybe?
And last but not least is my idea for if we Can't fix the city size problem. Instead, would it be possible to create 'sub-cities' almost that are pre-built and unlocked when we meet a certain threshold?
for example, when you reach a high population, you can choose to have one of the sides of your city adjacent to your region built into a 'downtown' that is already pre-build and stored.
I'm sure this would be easier to accomplish for the modders, as it wouldn't involve making the data used int he city any larger, just adding a few road connections and 'ploping' the city extension you want. Almost like the mega-towers but as entire blocks on the edge of your city.
this way you could just program it so that so many people come into the city looking for jobs?
There could be different 'ploppable' bits, like - a bigger university, an industrial estate that provides jobs and freight, even oil fields so that we don't have to waste precious space on this ourselves and instead just receive resources from it?
If that isn't possible is it just possible to make a new region with more cities, but directly next to one another? So that they appear to run into one city, but it's actually over three or four cities?
Just some ideas!