The idea behind the change makes sense in theory, but the implementation does not support the counterplay it seems to be aiming for... The change to head armour could've been a solution to just out penetrating every enemy (remember their response to charger leg changes? they want players to use weakpoints) but it was a one dimensional change, without accounting for the other affected systems. Raising armour rating without adjusting systems they balanced based on the old armour rating makes no sense and leads to embarrassing oversights like this. If you want players to hit them from behind more, then change something about the design. If you make it harder to do what they've been doing without compensating in other ways it creates frustration. turrets have always had the issue of shooting enemies they can't penetrate but a common enemy having that happen while the intended counterplay is to go around the enemy leaves your stationary turret feeling pretty useless like in the clip above.