Gavin Lowe of Game Kudos writes an article about realism in gaming, how it's essentially broken, and why it's not what gamers want:
"Take for example the hugely popular Modern Warfare 2. Many gamers would agree that it was a very realistic shooter. Excellent graphics, modern, accurately rendered weapons and absorbing gameplay, all of which lead to the argument that it is very realistic. But is it? I would argue no.
the case of the single player game, despite the accurate physics and the detailed aesthetics, regardless of how much I enjoyed the game, not once during my experience of it did I feel in danger. I was not in fear of my life and was willing to take enormous risks regularly to progress the game. That is not realistic. The “Army Of One” concept can only go so far. What are the odds of engaging literally hundreds of armed, well trained enemies and coming out unscathed whilst their corpses lie in piles tens high? It simply isn’t feasible."