I'm hoping against all hope that we can somehow get something like this as an anniversary treat. Charge me full price for it, go ahead, I don't care, I just need more animals.
Although I do constantly wonder where the line would be drawn for how different is too different. Like. the Masai giraffe, Arabian oryx, and probably the Nile crocodile and perentie could be literal reskins. And that's good, I think being just an actual texture swap is the target we should be aiming for here. Maybe there's some minor differences I'm unaware of between them and their base counterparts (never in my life would I have ever expected to read so much about the bump on the side of a Baird's tapir's face), but overall they seem very similar. Bighorn sheep would probably need at least a bit of remodeling done for its horns. But the rhea would need even more than that, requiring a model touchup and resize and posture change, and all of the added work that comes from those. The peccary would require a wholly new model even if it got to inherit the pig rig and animation set. Look at it, then look at the warthog and babirusa. Totally different body shapes.
I can't stress how badly I do want every single animal you suggested, but I've also got to keep stressing that we need to keep our dreams in check when hoping for a "filler" pack that has animals that would require more effort than some "full" releases. With any luck, though, I would love to start seeing biodiversity packs peppered into 2022.
