It would be immersive but it wouldn't add anything to the depth of the gameplay.
If we had already solved some gaps in the gameplay and in the "realism of gameplay" (such as the armor system and therefore also the combat system as a result), then I would also be in favor of a realism not linked to gameplay but to aesthetics.
I prefer to have different feedback from the game based on when I hit areas of the enemy body where there is no armor to cover and areas where the armor covers the body.
As long as there are no actual and real consequences to this, the rest is just an illusion.
Eventually it would become anti-immersive:
you would see a guy in heavy armor get hit, moan in pain for 1 second, then return to his "quiet" state while in the newfound delirium he yells "arrrhhhhggg" coming towards you with his arm raised while holding the weapon, ready to be hit again to repeat the pathetic and fake scene.
If the system must be realistic also in aesthetic terms, it is necessary that this aesthetic is not a facade but consequential to the gameplay.
Although an enemy has 10% HP, they move as if they have not suffered any injuries… yet in theory they should be on the verge of fainting.
But in the game the models are already too affected by the fallacious armor system, which being made of paper, they end up not protecting as much as they should.
This leads the model to die so quickly that the pain does not feel it.
There cannot be a gradual change of the state condition.
If, on the other hand, we had "realistic" armor (which means not only raising the armor value but intervening on the hurtboxes), then we would have a more gradual change of condition of the model (taking less damage from the hits, it tends to pass to a worse condition more gradually).
Of course, this worsening of conditions needs to be adjusted well, because if worsening the condition significantly decreases the speed of movement, it means that a character who has 10% ends up moving slowly like a turtle and there are few things that are they hate how much a character who is too slow.
So between the aesthetics as an end in itself which is then redundant and the gameplay, I vote for the gameplay.