Literally all of them
It looked like Auxiliaries were assisting officers on pursuits (they set up the roadblocks) would never happen in real life. Unless you change their title to reserve officers, or maybe have the ability for a reserve unit with different types of reserve officers. Fully trained, and less trained ones that would handle stuff like parking complaints. The fully trained reserves can fill in when an officer gets hurt, killed, suspended, and etc. But their access to you is for a limited time.
Administrative stuff:
Internal Affairs aspects.
Have a dedicated internal affairs division or detective (depending on size) that respond to different scenarios that spring up if the morale and mental health of officers is too low. Maybe investigate some high level complaints or a video gone viral. Place officer on investigation and take them off the streets, suspend them, fire them.
Union
Union negotiations on things like policy and salary. Have morale affect union relationship. Maybe negotiate pensions so that if you get a new mayor who messes it up you'll have a morale problem and you'll see lots of cops leaving/retiring. A nice little challenge that happens in real life.
Proactive patrol events?
Are there going to be dynamic events that your patrol officers will stumble upon based on the neighborhood?
Ability to customize uniforms as well. Color, external vest or not, what type of hats, etc. Maybe have certain things requested by the union which affects morale.
Types of shift schedules that you'll need to experiment with to maximize officer morale, effectiveness and keep their health in check.
Community events that change the relationship with citizens and how good recruits are for your town.
With games like these, try and make as many dynamic situations as possible. I've played and seen other sims like these, and shit gets boring real quick. So even if you have lots of different scenarios, try to come up with as many different aspects for them as you can. Arrest warrants for as many different things as you can think off, different motives for certain crimes or suicide. Just keep it as fresh as possible.
What's the biggest population setting you're considering? I feel a population of like 5 million would be a nice challenge but incredibly overwhelming, but I think you should support populations up to 1 million if you haven't considered it yet.
Overall, I'm very excited. I think you guys hit the perfect balance for a sim like this. In depth, while being completely engaging.