City rpg can't exist in it's current form. A vast improvement in my mind would be a two teams base raiders where one team, criminals, decides where to plant drugs while police try to raid all the drugs.
Each criminal can place one drug lab, which is just a small 8x8 plate. Standing on the drug lab gives you money every second, and you can use the money to either barricade the building, buy better weapons, or bust teammates out of prison. Basically you'll respawn every ten seconds if you die as long as your drug lab exists, but if police manage to bust your drug lab, you are dead until a teammate can bust you out if they choose.
Police will start slightly more armed, and every time they bust a drug lab they earn a pool of money, which can be used to upgrade the arsenal. Whoever holds more drug labs by the end of a timer will win. So basically cops need to bust more than half of the criminals to win, while criminals need to defend half or more of the labs to win
This type of game will promote barricading, objective defense and teamwork as criminals pick strategic locations to build their lab and police coordinate raids. It incorporates some building as well as good use of money as a means to either support yourself or support your team. It's not an rpg in the sense that you can't roleplay certain jobs, or start a business, but I'm sure there could be criminal/police classes such as a trapper for criminals, who can set up booby traps, or maybe a breacher for police, who can break through structures. An economy could exist in some sense if you add specialized goods, like maybe whoever sets up a lab in the hospital can trade medicine with whoever sets up lab in the grenade building.
This concept would also solve the main issue with base raiders, which is that there's no end goal and anyone who joins early and has enough time to amass resources will dominate the game. In this concept there's a fair and neutral playing ground for both teams to advance and reach the objective, either solo or as a team.
