Okay. Now, we have npcs/beasts looting random things, possibly things they don't seem to have (or even couldn't have at all, like weapons looted on beasts!), and nearly never everything they should have.
Instead of looting random things with several probabilities... Why not having enemies giving precise and constant loot corresponding to what they wear/what are their animal parts.
I see you coming... "Yes, but then things will be to easy, plus, if we want to make the system more realistic that isn't better than the older solution, blablabla..."
Indeed. But I haven't finished yet.
Instead of having a random part concerning the looted items, why not having a random part about their quality? Thus, a simple table would be enough to determine the given loot, and it would also include the possibility of not looting some parts, through the model of the "that's broken, unusable, so we don't loot" corresponding to a quality zero.
Though it would be much more probable that people loot at least some damaged but usable parts, instead of nothing, if we consider the distributions of probabilities like Gaussian functions.