I would love to see some animals added like an iguana or monitor lizard like the Komodo dragon. Having reptiles apart from crocodiles adds a new mechanic to the game, which I think is nice. They could add the iguana to Mississippi as an invasive species. Also adding seals could be fun same mechanic as like the rabbits, but they don't have a burrow, so instead they come out of the sea. This also could go for a hippo instead, during the day it is sometimes visible in the water. And a night it comes out to eat.
Coming back to the iguana and monitors. They can make them slower and harder to spook on rainy days and early in the morning when they are just starting to sunbathe. But later in the day, being way faster and harder to sneak up on. Be free to add to this, but focus on adding new things. For hunting with more variety. Maybe even to existing animals.
Some more animals I have thought of that could be added for a nice change,
Badgers (giving them burrows and making them more aggressive when close to one) this could also be added to warthogs and foxes.
Animals that use the trees. (This will be hard, but it's just an idea)
Otters and or Beavers (giving them burrows in and near water)
marmots in SRP (a lot like rabbits, but it feels like they can do something different with them)
Baboons (They don't tend to go up in trees as much, but they have very different behaviour then animals we already have, so should be easier)
Penguin (even though they are normally not hunted, could be a nice addition)