Personally, I would also like an ambiguous_body_type tag. Semi-anthro is... okay in some ways, I guess, but not really sufficient in others. Notably, images where there is not enough shown of the creature to be able to say whether or not it is feral, semi-anthro, or anthro.

Is a disembodied canine penis, for example, feral, anthro, or semi-anthro? If a human is engaging with a disembodied animal-like penis, should that be tagged bestiality? Because it is, sometimes, and other times it's not, and as far as I know there's really not any clear ruling on what to do in those cases (I've asked and gotten no response).