I'd like to see criminal elements not immediately jump to the atypical cookie-cutter "Fuck outta here pig" dialogue when someone wants to get out and build a rapport with them. It's borderline unrealistic, particularly from criminal entities that should have the understanding of not bringing undue attention or foul relationships with law enforcement.
People who build a good rapport with cops & vice versa are less likely to be fucked with in a negative manner. This isn't just a "well just because Augustus' has it this way doesn't mean it is like that everywhere"; it's genuinely across the board. Those who have done hard time, or especially the old heads, know not to draw 'heat to the cut'.
It's not uncommon for felons/gangmembers/dealers to come up on the street and dap up with me or other officers/deputies they recognize. To real criminals, it's all just business. Your job is to try and catch them; their job is to try and get away from you. Other than that, you both recognize eachother with respect. Unless, of course, you were genuinely just an asshole to them in prior encounters. I know of a few Deputies who would likely get swung on at first sight with certain folks.
Granted, the younger crowd who aren't as seasoned, are certainly more volatile. I lost a fellow cop here in Georgia to abunch of young, newly minted gang members. The younger crowd, though, are only tough when others are there to feed off eachother. Every time you get one by themselves, it's almost night & day with the difference.
With the LEO side of things - probably would like to see more character development & relationships being built between cops. Lot of 'billy-badass' archetypes running around, or people with the personality of a T-800.