First: A simple suggestion for the future is adding a variable factor into each call out, selected at random from a set, with a different action required for each. This is already implemented into the shots fired call out somewhat.
E.g You might find the perpetrator has already left the scene and you are required to make a patrol / search of the area; or you find an unconscious or injured victim or Police Officer and are required to call in a Paramedic crew; or all of the above. This could work for muggings, shots fired, suicidal person, etc.
Another thing: Is it possible to ratchet up the difficulty in finding the location of the callout? I'm not sure what the waypoint / "gps" system allows but it would be great to be given more vague information requiring the player to work a bit harder to find where they need to be (as in real life).