Currently when the player is picking up an accessory for his weapon (suppressor, optic, etc.) he just have to left click and the accessory is instantly installed on his weapon.
for a more realistic gameplay and to limit accessories advantages abuse each accessories should require a delay to be correctly installed.
for example when mounting or dismounting a suppressor the delay should be of several seconds (5-6 seconds)
same thing for mounting and unmounting an optic device :
to correctly install a scope the player must carrefully place it on picatinny rail then must clamp the thumbscrew. (which should require 10 seconds at least)
the instantaneous accessory mounting/dismounting is too arcadish and unrealistic.