After a bit of thinking, I started to wonder whether the flash hider may need a slight tweak in availability. One of the issues that NWI encounters with sandstorm is that locating enemies and incoming fire direction is quite difficult, so much so that it required the introduction of a kill cam variant. Now, being hidden and hard to locate is something that fits a selection of the classes, primarily those that have also been granted a suppressor (the sound of which is distinct and sometimes seems to set people to search instead, not quite related to the topic).
The Flash hider, however, is widely available for the smallest possible amount of supply points, only 1. While it may not mask the sound of gun shots, it does greatly hamper the ability of the enemy to locate the shooter on screen. A sound can provide a general direction, but spotting the exact location among the highly detailed environment can be challenging. In sandstorm, not only is the muzzle flash visible itself, the flash also notably lights up the surrounding area of the shooter. That area highlight is absent with the flash hider, which why it may be the most powerful attachment in sandstorm.
I suggest looking into the flash hider availability as it is the most available attachment in the game that adds to a recognized problem.
To those reading, I am curious to hear your thoughts.