I agree they shouldn’t hesitate adding endangered animals to cotw. There is no way to add complete new mechanics to this old game. And it’s needed for variety.
But if they decide to make a new game one day (I pray they will do a combination of the angler and hunter in one game btw) they should also add endangered species but with restrictions:
Add mechanics were you need first and foremost care for your reserve and animal population. So the classical „grind“ only is possible with non endangered animals.
For some animals you got to buy licenses or pay a fee something like wolfs or pumas on silver ridge for example. And some animals like lions and tigers (one day elephants?) you are only tasked to hunt if they attack humans and requiring you to track down and identify the right animal (of course afterwards your able to display your trophy) .
As an addition, after you cared for the reserve properly, you can one day restore the population of those endangered species in your reserve. Maybe, besides of creating a main story line with cutscenes about the reserve and its history, add side quest lines which focus on the recreation of certain animals habitat (buy new animals and let them free, reduce their rivals/predators, track down poachers etc.).
I’m telling this because I’m bored of just trophy grinding and thats why I’m only interested in new reserves or other dlc‘s. The endgame on the new game needs to be more rewarding. How cool could it be to sell hunting licenses for Elephants to your friends in multiplayer on your map after you did hard work do successfully and stable reintroduced them to your reserve. That’s a lot more personal. This could begin by just tracking your population with wild cameras.