No, you are absolutely wrong here. Armor prevents a portion of damage/adds damage reduction. If you have less armor, you are way easier to be killed, which is technically a nerf in this situation.
To Clarify: HTF is NOT getting an HP buff. They are having their HP changed around from 200/200 to 250/150 for MK1 and from 225/200 to 250/175 for MK2.