ARMA 3 is not unrealistic, the game itself is pretty good. Maybe the fact that they tried to take it into the future might be but that is just the storyline of the game. Physics are pretty good. So are ballistics. Remember the game is still in beta testing. If what you don't like is fighting futuristic iranian soldiers the solution is just to download a mod and put modern russian, or terrorists in there, instead of the iranian soldiers.
--EDIT--
And yes flying does suck! But not the infantry. And that COD, Battlefield and unrealism crew is just getting DayZ.