I use the VTS ballistic from l'etranger (excellent)
http://forums.bistudio.com/showthread.php?156211-VTS-Ballistic
This mod make the wind affecting infantry projectiles.

and in arma the wind direction change every time and to much 'sometime from north sometime from south...)
in real life most of the time the wind don't change more than 30 degrees.

I'm windsurfer ;) while more than 25 years (in France) and in real life I can confirm that the wind direction don't change every time like in arma (or only in thunderstorm) (if it was, it would be really difficult to do windsurf or sail-boat !)

so when you engage an enemy from a long range , sometime bullets impact are on the left of the target and sometime on the right, it's not realistic