I'm all for more realism in an FPS game, but then the realism also has to apply to the NPCs, who have unlimited ammo, can see through walls or worse, shoot through them, who have no fear and thus not hide or not long enough, don't sneak around, don't have imperfect control over their actions.

I don't have a perfect game setup and am constantly hampered by needing to do two different things like locomotion and handling with only my left hand, thus using cheats is standard for me to compensate for the imbalance. Also, sometimes I just want to enjoy a walk through the environment without constant fighting (Far Cry 2, 5).