-Make the city part of a bigger world, show international news of the time, give us the sense of dystopian world happening.
-Make an evolutive space, as in Novigrad in TW3, but more intense. Destroyed buildings(Or some new ones being builded), people in/emigrating, political impact (Like elections, war, "national security issues", etc).
-Do not think it is enough customization: Make consumable substances have good or bad long term consequences, drugs, meds, foods. I see prosthesis in the trailer, I would love to be able to modify mines, different materials, engines, brands, energy consumption, etc. Give us both the feeling of irreversible change (like loosing a limb on a fight and getting prostheses instead) and the chance to reboot some features we didn't like (Like learning martial arts at the "Matrix" style).
-And as it its like placed in "the real world" you should take a lot of time investigating all kind of vanguard science, physics, biology, computer-science, so you can make a solid plausible approach, and make all the atmosphere a lot more credible.
-Oh, and one last thing, if you can retrieve data of what the players are mostly doing, you could use unsupervised or real time training Machine Learning to make things more difficult to those meta-game players, and to make the game more vivid. We would love things to change based on the unconscious behaviour of the player base. No other game has made this, and if you want to, I would love to help, but i'm still learning LSTM Neural Networks, hire me in a year and we'll do.