I don't get the people who complain about the amount of shooting and about the lack of realistic emotional responses to said shooting. They are unrealistic games. Do you also get upset because of the supernatural aspect in the games? Or the insane and impossible jumps Drake pulls off? Or the unbelievable set pieces that happen constantly through out the game? If not then, then you don't make any sense. If you do, then you want a completely different game because Uncharted was never meant to be anything but bombastic and unbelievable.
As far as the shooting, that's one of the core focuses of the gameplay. Being realistic is not. Having Drake shoot maybe 5-10 people and maybe a couple of fist fights for the entirety of the game would be so incredibly boring. You're better off watching a movie or visual novel if that's what you want. I seriously hope the developers do not listen to these complaints because it would ruin the game.
Maybe they can put a special mode in the game that removes all the enemies so you can just run through it. No killing!!!

Maybe put a stamina meter on him and make him become extremely tired very quickly to be more realistic.
Edit: Or maybe they could add a realistic mode that has one shot kills and effectively make the game unbeatable.
Edit2: And an emotional mode where as soon as Drake kills someone, he drops to his knees and starts crying and the player gets a game over screen. ;P