GTA 6: 8 Things It Must Learn From Red Dead Redemption 2
2. More Interactive NPCs
When it came to the NPCs in GTA 5, the only time you really had any sort of interaction with them (not including any sort of mission) was when a) they tried to fight you for whatever reason, or b) when you came across an altercation in an alleyway where you would typically have to drive someone away after. Other than that, they just minded their own business for the most part.
But where's the fun in that? In RDR2, the AIs want to fight you if you just stand near them for a matter of seconds. They're featured more heavily in the game, making it a much more believable world while playing the game. It felt like you couldn't go down the street without someone getting involved with your life.
At this stage, it doesn't feel like this even needs to be said. There's always a boatload of NPCs roaming the streets of Rockstar's games, so why not actually do something with them? Obviously they don't all need to be interactive - otherwise it would just be pure madness.
However, it's a good starting point to make them do more within GTA than just walk around.