Why? Genuine question. What would change for the animal in real life if it were in the game, even when if it might not be really widespread in zoos? There sure are some animals I'd like to see that are endangered. But mainly because I often see them in a zoo or they personally mean something to me. Breeding pixel animals does not really help critical endangered species and I come to a point after two years where, as much as I love this community, most really do not see or use PZ for education purpose (and that's totally fine!) They would, for example, see the asiatic lion as a clone of the west african lion, not caring if it is critically endangered or not.
I don't think choosing animals for statuses would be a good way to go. That doesn't mean we couldn't have a critically endangered pack with critically endangered species that are common on zoos. But for any other packs, I would definately choose different parameters.