the accuracy of ennemies controlled by AI is too high : when playing in daytime ennemies can too easily spot you through walls, rocks, trees and even under water, and in night-time they're still able to shot you right in the head from 400-500 meters whereas you're hiding...
Ok ArmA III is a realistic simulation, but AI reactivity is too damn high, whereas where you're at 3 meters in front of one ennemy controlled by AI he acts as if he was completely blind...
That would be great if you did something to fix this problem : a more realistic accuracy for ennemy soldiers, and a AI which would be sensible of hiding or not : that would be harder for AI to spot a player if he's hiding through obstacles as bushes and rocks...