This is really interesting.
Black Jesus made a bunch of good points I'd like to build from, and introduce my own.
City sizes (both population and area) would pose different challenges. I'd like to see a small metropolitan area with the various culture groups; having to deal with the various language barriers that are directly associated with it. Additionally, large area maps that make you spread out your resources and deal with long response times and remote access to specific location. If you have an option for a map designer/city builder - this could pull some pressure from you for meeting everyone's specific needs.
Coming from that, I'd be curious to see what kind of modding support you'd have. Would you release the game on Steam and support workshop endeavors? As you can tell the community here has been know to outperform themselves when it comes to modding for further immersion and activities.
Sheriff's Office and other tidbits - I'd like to see where the player character is the Sheriff and not the Chief - being directly elected by the people. This would allow that character to go against, or with, the local/county government to gain funding and fight against municipalities for funding and officers. This would create a dynamic where you have to keep the people happy to stay in office, risking going against your government, all while remaining competitive to recruit some of the best LEOs in the area. Additionally, some dynamic to demonstrate the current issues that law enforcement agencies face with local/county/state and federal governments. Attempting to keep everyone happy while maintaining your own morale and manpower. (And, that's still nothing about housing inmates and the judicial system).
Policies - I like the concept of setting policies and hope that they're open to a lot of customization. This would allow for some international use (looking at the UK) for a completely different play style. Additionally, differences in pursuit polices, when helicopters are utilizes, specialty unit call-outs, and things along those lines would be interesting to tweak to your person (or familiar) standards. (Granted, along the lines of what your gameplay actually allows.)
Overall, I love the concept and would by into it - even at this phase. But, like Black Jesus said, I think you're on the cusp of gaining a lot of positive attention in relation to your project.