The role of the patrol is incredible useless as they only engage hostiles they stumble upon. In no world I could imagine the lack of response this role has to events in the sector. A patrol should respond to distress calls from allied ships.
The defend position command is way to limited in its range for effective response to events. You can basically see that a patrol in a Khaak infested sector Never responds to Khaak attacks, never react to pirate activity.
The role of the police to scan for illegal Items is even more useless. The player can only employ police in owned sectors and then what should they do? If the player owned police engages faction ships the only result is a loss of the relationship.
The police also does not respond to distress calls and only acts on events they stumble upon.
Instead, the police should look out for events and activate patrols to engage to threats. Even if a player has a patrol force in NPC territory and the relation is good enough, the player patrols should help the local faction to respond to threats, and vice versa.
Of course there need to be some settings. Having a light fighter patrol engaging a Khaak station of Xenon K would be incredible pointless. There would have to be settings as to what kind of theat a patrol force is allow to engage.
I know this is a complex issue and has deep balancing implications. It also touches on piracy and other things. But I would say if you look into this you might find it also interesting to make piracy a better feature, a real threat instead of randomly spawned Minotaur's magically dropping traders out of the travel drive and make them using a flee command that most often is so bad that the trader would be better off to just ignore the dumb and slow Minotaur... Piracy is just an annoyance and lacks any grounded logic. The police force is not uncovering pirate ships even if it is obvious that a Boron would not fly a Minotaur around.
Pirates should have their challenges too, and therefore also should pose a challenge. Regular raid attacks on poorly defended stations should be a thing. Piracy in core sectors should be almost impossible on the other hand. But often you can see that a SCA ship mindlessly kills a trader only to get wiped from the strong patrol right next to it.
With a proper patrol and police force you can make piracy great again as well.
And I miss the good ol pirat asteroids in the outskirts of some sectors...
Perhaps all this is too much of a change for X4, but at least put it on the list of things that have to better in X5.

Thanks.