Don’t get me wrong, I know that Grand Theft Auto is about destroying, killing and creating as much carnage as humanly possible—as it should be! But in the GTA series more specifically, I would love to see more options for the more conscientious player; perhaps something as simple as being able to shoot an NPC in the leg to disable them so they can writhe infinitely on the ground until you leave the scene or until paramedics come revive them. This was sort of possible in GTA IV, though it was 50/50 chance of them successfully writhing.
The best example I can think of is True Crime NYC. You could blast your way through the game, or take the time to make non-lethal neutralizing shots and arrest the perpetrator. Or not arrest them, it didn’t matter—and that’s my point. It was equal effort on behalf of the developers either way. In Grand Theft Auto’s case, think it would create a fun enough challenge for anyone who wants to take their game a little further—as well as create a more immersive game play experience by simply giving the player that choice, whether they use it or not. I have played and beaten Grand Theft Auto 5 so many times anyway… I just think it's fun coming up with new ways to play the game; like forcing a bad guy character to be a good guy. :p