Numbers

Any representation of something numerical in-game retracts from something we call 'realism'. Real life is completely numerical, how heavy this optical mouse is, the friction of this flooring - the number of meters I can sprint, the amount of real hitpoints I have (subjective to real life hitboxes) is all entirely based on numbers.

But observe your surroundings for a second - you'd never know to look at it, would you?

Games are also based on numbers, just far, far less of them. The floating point clarity of the path this piece of paper would take through the air when dropped to the floor could be thousands of figures long in real life. In games, it'd be no where near as complex.

Less complex, and a lot more obvious. Look at your HUD - health is numerical, ammo, carriable weight, the damage of my sword. It's not even specific to any genre of game - the remaining health of your refinery, the movement speed of your newly researched attack chopper, how many enemies left to kill... Everything in games is too frequently, too obviously numerical. So lets fix this.

In Battlefield - you run across an open road to an alley on the other side. About half way across, you realise this was a bad idea. Enemies materialise from out of a wall of smoke further down the road and open fire. Bullets whine intrusively as you half stumble to cover on the other side. Just before you get there, your view skews slightly, and your character lets out a groan. You continue down the alley to a darkened porch, away from the advancing troops. You press the hotkey for 'examine wounds'.

No, no. Wait, stop. I was going to suggest a method of health system based entirely on visuals. No HUD, you have to be out of harm's way for a moment to check how badly you're injured, then decide what to do from there. But if you were shot, you wouldn't need to check visually how bad the damage was, the pain alone would be enough to give you some indication. You could make up some reason for it, "all our soldiers are given a couple of Neurofen at lunch time," but that'd just be insulting. Thinking about that feature, where under a limited number of animations and texture sets, your character observes his leg, arm, stomach, shoulder for wounds. It would be gimicky and boring. Not to mention laughable in terms of authenticity.

Besides, damage in games has been done before. Your already lacklustre movement speed is often halved in Swat 4, having taken a hit or two. Suddenly the thought of tackling that whole next floor at a snail's pace prompts me to restart the mission. Is that an effective implementation of realistic damage?

Yeah, well.. Games still need to be less obviously based on numbers. In another FPS example, there could be an animation to check the number of rounds in a clip, rather than the 2D HUD counter.