The problem when introducing "well what would really happen" scenarios into it is that if you're talking about an actual combat situation I wouldn't have the choice between ducking and standing or staying within the invisible confines of a few hundred square metres would I? The list of differences between games and reality is rather long, so why is weapon damage the sole facet of FPS games that 'defines' realism?
The reason games are balanced the way they are is mostly due to the very limited interaction you can have with the environment within the game, even if you look at something like OFP/Arma, seen as the pinnacle of realism, they aren't even remotely realistic... just slower paced and clunkier than your average, which is about all FPS games can offer you, different paced versions of Quake 3, regardless of how you skin it.
Hardcore wouldn't be an issue if it was more aptly named, it's current one denotes an increased level of skill or something equally as misleading in playing it when in fact you're killing tuned game-play balance in one broad stroke so people who aren't that quick or can't aim that well have a bit of a chance of wracking up a few kills anyway.