ArmA2 is good but not far enough toward realism. The more realistic the game the better the guns feel, instead of being boring little "ping ping ping ping ping ping" things they become something that makes things die
People have this stupid idea that realism is boring, dull and nothing ever happens, this is not true. Realism means that a shot to the heart will put you on your ass, an RPG will only tell the Abrams where you are, and your leg is broken for good.
Authenticity is what people often think of when realism is mentioned, yes, an authentic cold war would be f**king boring because nothing would happen.
Authenticity: uniforms, language, tactics etc. How things are done.
Realism: weapon damage, running speeds etc. What happens when you do them.
Realism all the way! And authenticity to a certain degree, but there are certain times when authenticity must be sacrificed to make the game fun, for example, I know waiting all night for the mission to start would be authentic but screw that

ArmA2 is a good mix, but needs more realism.