As always, great post topic!
And YES, the game is in-variable-y against players. We've all seen Fun 2's posts with the myriad of variables just for a single weapon that Rockstar can tweak at a whim, literally changing the game for any object or action at any time they feel like it, leaving players in the dark and guessing as to what's actually going on behind the scenes.
Rockstar's (semi-understandable) reasons for ratcheting up aggressiveness include:
* Difficulty increases as players gain rank.
* Player access to new armored vehicles and high-powered weaponry against the LSPD and NOOSE who have the same weapons and lack of armor.
* GTA Online economy: Players are making too much money too quickly between updates. Plus Shark Card sales and giving players incentive to work for GTA$ so they can buy new items. Makes sense to some degree--in Watch Dogs, players have massive amounts of easily-hacked money, but with virtually nothing to spend it on.
Player's understandable response to this:
* Kamikaze NPC cars are just blatantly obnoxious, constantly breaking game immersion--it's like having a "modder" screw with your game...except it's Rockstar behind the wheel. e.g. Real-life drivers quickly turn away from an approaching car; not steer into its path. Many NPC vehicles will actually do just that--steer into your path, or suddenly do a U-turn into your lane, or slow down as they cross the street ahead of you just enough as you approach so as to collide with you--unless you suddenly change speed. This is no "accident" or bad scripting on Rockstar's part; it's a deliberate action to impede player progress and make them fail whatever they are doing. It gets ramped up when you have a wanted level. Just go back and drive the same streets/paths with traffic on in a contact mission, and notice the vast difference.
* Downright ridiculous game play--ever end up trying to fight a literal swarm of LSPD and NOOSE both on the ground and in the air at a four-star wanted level at the LSIA in "Hostile Takeover"? It's virtually impossible. Epic trolling; just quit the session, because it will be an endless gang bang of LSPD and NOOSE killing you over and over again until your time runs out. Same thing in other situations, like Dead Drop or Moving Target... the minute players get a wanted level and end up 20 feet away from an armored car or chopper, it's a massive, endless killing fest for the cops. And an epic waste of time and money for the player(s).
* Gang attack NPCs who arguably are not wearing any armor taking three or more point-blank shots to the torso from the Assault Shotgun before they're dead (e.g. Families' project building in Strawberry). Meanwhile, you're toast if they get even one point-blank shot at your torso.
Ii could go on about invisible shots fired at players with no cops within visual range, cops and NPCs seeing and shooting through walls, etc.--all with video evidence, but you get the idea.