ARMA's firearms do NOT sound realistic. They sound as if a person with a cheap microphone has stood way too close to the source, resulting in severe compression due to the sonic overload, and NOT the way a person would percieve an actual shot going off, which would be ear-splitting instead of the subtle "pop" we currently have.

You need to place the microphone further away from the source if you want to accurately capture the sound of a firearm. Then again, I honestly get the impression that they, many times, just rip the sounds straight from youtube videos.

The flight engine was, honestly, dogshit in ARMA2 as well, so I wouldn't put it past them to let things like sound and physics stay pretty much the same. Unfortunately Bohemia Interactive has a habit of letting the community finish the game for them.

This definitely needs to be adressed, alongside the subpar helicopter flightmodels.

Absolutely correct. One of many features that need to be adressed in order to improve the polish of the game.