3 less damage is a considerable nerf to its damage potential and definitely impacts the weapon's effectiveness regardless of how you look at it.
The fact that it is pierce guarantee its effectiveness up to 15-20 base damage on pretty much every armors.
Then being able to have effective thrust + unbreakable shield + very fast speed and still be able to wield the dagger makes it OP. Even though one could still argue that it requires skill to manoeuver around, but with a shield its like a fast as lightning lightweight version of kinngrimm
but there is no need to try to call for another nerf, at least for a few months.