How you guide the near inevitable growth of the city these mega-corps seek to build from the bones of the old will be graded by how well you just happen to align their interests with yours.

These megacorps won't simply offer to fix these problems, there has to be something in it for them, considerable amounts of it.

Your city needs floodwalls to keep rising tides from inundating low lying neighbourhoods, it needs highly productive vertical farms to maintain disrupted supply chains to local shops, it needs public services central authorities are less & less willing & able to provide nor subsidise.

The first plank of the game's design philosophy is that you can't directly dictate what these mega-corps do. If not because of outright game rules, then because your city cannot survive this changing world without the resources at their disposal. There's many deals offered, always with catches.

A save starting with a contemporary city in the near future in a period of historical crisis. This city is [LAYER 0] of the city that will grow around and above it, the organism upon which these parasitic, mega-corp growths will latch onto.

Personally like the idea of the latter. Can really play into the idea of a tiered dystopian city, this public authority trying to maintain the utilities and systems sustaining the layers upon layers of laissez-faire development. I think it would need to start with a pre-existing contemporary city.

So how does the city builder staples of a mayor and city hall/urban planning office fit into that? Does the game position you as a development arm of one of these corps? Or a beleaguered public authority that must balance relations with these corps and the people that inhabit the city?

Would need a thematic & interesting way of approaching the gameplay of how you relate to & interact with the city, imo. Front & foremost being that the primary powers within such a city would be the global/interplanetary mega-corps who by the conventions of the genre would have eroded civic power.

*Million of screenshots of posts complaining about cims crossing at places where players removed pedestrian crossings in C:SL2*