I think there should be more missions such as:
Robberys (Banks, persons, stores, etc): I'm sure this has been said many times, but I see nothing of it in the suggestions forum. A bank gets robbed and alarms sound, there are many units responding and you have to catch or neutralize the suspects. Another type would be a person robbed of his money or items and you must catch the thief and return whatever he stole to the person. Another would be a store such as burger shot reporting to be robbed and you must get the robber(s).
Kidnapping: I think there should be kidnapping missions where you must go and make sure the victim gets away safely and unharmed.
Joining in chases: I'm pretty sure I read this somewhere before, but don't see it here. There should be chases already going on where you can join as a backup unit.
Domestic disputes: Fights going on between a man and his wife where you must go and break it apart.
Shoot outs of gangs: Gang wars, where the officers with backup must go and stop before innocent people get harmed.
Car crashes and emergencies: The officer must go and control traffic and people when a emergency such as car accidents, people needing medical help, or fire go on, and must stay until its solved.
Thats all I can think of for new features.
Suggestions for existing features:
Make verities of suicide attempts, such as a person standing on a building threating to jump off, or at a bridge.
All I can think of as of now.
New features:
A radio system similar to the one of police pursuit mod, a sound on your computer of a scanner, and a car tuned to Independence FM where you can hear a police scanner.
EMS back up: Be able to call for EMS is a person is down.
These are some of what I think should be added to the mod.