I just hope "pulping" won't be an actual verb ingame, as "strike the swordsman in the left lower arm with your +iron mace+, pulping it!" sounds... bad. Hopefully he just means it as a technical term.
Skin doesn't make much sense as an undead, and neither does having every single product of the creature reanimate. Skin has no structure whatsoever, unlike bone or muscle, and really doesn't have any way of hurting people even if it did flap around. Right now, the skin is treated as having the mass of the entire creature and so breaks bones by "pushing." Also, what's to stop necromancers from just making people's leather clothes kill them if skin reanimates? What's really that different between tanned leather and leathery mummy skin?
Bone also doesn't have much structure. You need tendons and muscles to keep it up, otherwise the skeleton just crumbles. What keeps it together in DF is the necromancer magic, so skeletons raise and attack you. The same thing can be done with muscle, hair and skin. A hollow man, made only of skin. You could argue that it can't hit hard but then again, it's using magic to keep things together, so it probably could. I would be okay with necromancers reanimating tissue, bonding them together to create hollow, hair or muscle only monsters. Of course, they would need to be destructible.
That's the thing though: bone is rigid, and so has structure, while muscle contracts/expands, giving it motion. Zombies have at least one or the other, so they have plausible structural support, with the aid of a little magic, but if the magic could just make anything structurally stable enough to animate, why would pulping work in the first place? If skin, which if separate means it was cut up to be removed, can animate, why not unrecognizably mangled limbs?
Currently, all butchery products except meat, fat, and nervous tissue will reanimate. Shouldn't the act of cutting up a creature into it's individual component tissues break it down enough for it to not work? You can't reanimate a leg, but you can reanimate a solitary leg bone if you butcher the leg? That's how it works in the current release.
I can understand individual animated bones, skulls, and mussel shells (though they shouldn't be lethal, much less equally lethal to a complete zombie), as they have rigid structure to them, but animal peelings?