More violence and political incorrectness. The fun thing about the GTA games on PS2 was causing total chaos and destruction and merciless killing civilians, preferentially with cheat codes ON to access all these juicy vehicles and weapons. GTA games have no good story, no good gameplay (they are basic TPS with racing segments), there's no reason to play them other than creating chaos. But it's 2019 and they still don't allow the player to kill children, the gore is being toned down since Vity City (why can't I dismember people with kanatas anymore?) and R* cucked out with GTA IV planes.
Basically R* plays too safe and release the same game over and over again for easy $, while still pretending to be "counter-cultural".
Edit: another thing to add. When GTA3 was released, the gaming market was being bombarded by conservatives who wanted to control games. GTA3 was basically HUGE middle finger to them. If R* wants to have credibility again, they need to make the villain of GTA6 a feminist and allow the players to kill and dismember rainbow-colored ANTIFA-like enemies, just for the lulz. Also, no more good hearted black characters who are "forced into criminality". Make them full fledged psychopaths just like the white characters. Stop being scared of being viewed as racist.