As much as I love realism in FPS games, it still needs to be fun. The idea of having your head move independently from where your gun is aiming was a huge thing when I discovered it the first time (think it was Operation Flashpoint). It was a bit awkward initially, but hitting the Alt key to look around became second nature. Plus, it snaps back to gun aim when you let the key go so you can quickly look around while still covering your target.
Arma also added more weight to the player character, where running uphil actually slow you right down (some games actaully make you run faster as your horizontal speed stays the same, yet you are going uphill...). And look down, what do you see? Shoes!
The sounds in Mirror's Edge was fantastic (actually, the whole game was awesome) and those little touches added to the realism without taking any fun away.
At the moment my favourite mod is the realism mod for Far Cry 3, where the map, HUD and aim-thingy are gone and its just you and the gun. If only they had the awesome map from FC2 in it and it would be perfect. These things add realism and at the same time add a different type of fun. It is now not an action shooter, but a survival game.
Not sure who played Trespasser, the Jurassic Park FPS. It had a really interesting, yet risky interface. The player was a woman, and looking down you saw your chest (cleavage and all). On the one boob was a tattoo of a heart and your HP was represented in how full the heart was. The game played like crap though. In order to make the game handle more realistically they had a rotating box simulating the player's movement and bob. If the obstacle was too high for the box to "roll over" the player could not walk there. In the same vein if the box was teetering to close to the edge of something the player would fall off. The game had GREAT aspirations and very clever ideas for the time. It was a very different way of doing things and ultimately failed to translate into any amount of fun.
I have only seen the first person trailer of GTA V and it looked cool, but very much a PR video. Will Google some actual gameplay. Sounds interesting.
