Aren't the sides supposed to be completely covered in solar panels?
> Navigation is super easy. No getting lost in the city.
But your maps need to be inherently three-dimensional because of the verticality. Usually getting around in a city only requires a two-dimensional map until you enter the building at your destination.
> One single [...] transportation line
In other words, a single vehicle breaking down can take down the entire transit system.
> One straight uncomplicated pipe infrastructure
You still need to branch out from the single pipe in the same way as in a conventional city. Also, "one straight pipe" is a really bad idea because of the same issue as above. Good engineering is all about avoid single points of failure.
> Incase of emergency easy and super fast evacuation, everyone simultaneously 'spills out' of the walls on either side.
Into what is mostly inhospitable desert.