A common limitation of stealth game is enemy sight range, to compensate, enemy hearing usually go further than sight.

Usually this isn't a problem because the game doesn't have huge empty spaces but from time to time you find situations where you feel like the enemy army is half-blind.

This create a scenery where you can walk in plain sight of an enemy as long as you are a far away and moving quietly.

Well, ducking makes you move silently but the end result for the player is "if I'm ducking enemies can't see me". It's almost like you turn invisible or something.

Ducking Op.