Here’s an interesting interview on that topic with Dr. Malcom Davis, a lecturer in Defence Studies with the Defence Studies Department of King’s College London. Dr. Davis says current games certainly have some realistic elements, but:
I think that consumer military simulations are never going to be totally realistic because ultimately people don’t really die or get injured, and thus the fear element is never going to be there. I think that what is missing is the chaos of battle. Too often I see tactical engagements unfold on the screen and everything is relatively clear, wheras in real combat, the elements of chaos, unpredictability and confusion predominate. Look at sequences in movies like ‘Saving Private Ryan’ or ‘Band of Brothers’ to get a good example of what real combat is like. The game that comes closest is the Call of Duty series on XBox 360 in my view.
Finally the combat environments are complex, and what is missing, particularly in an urban environment, are civilians mixed in with military forces. To return to the medium of film, ‘Black Hawk Down’ portrayed the complex urban environment accurately, wheras some computer games have literally empty streets.
I played Call of Duty on the PC–as close to a real combat environment as I ever want to get, thanks!