This has been empty for awhile, but I got another one. Unless this hasn’t been mentioned already: your zoo can get “Star animals”. These animals are either babies, or rescues that seem to become very popular on social media. You can expect to see an increase in the amount of guests. I also think a cool feature would be you can further market this animal: like you can sell merch and children’s books based on this animal.
Also, bring back ambient animals. Pigeons show up, squirrels may appear, small frogs live by bodies of water, may even spot a deer or two on the edge of the zoo! Depending on where you are the animals will change, but I think it would a cool feature to make the world more lived in. Likewise, maybe you can even set out items or areas that increase the presence of these ambient animals. Like your zoo has a nature trail or wetlands area.
Also, going off the Planet Zoo criticism thread, I like the idea of a more “lived in world”. Outside of the ambient animals, special events can happen. Maybe the local wildlife law enforcement stopped an illegal trade, and they need you to care for the animals! Maybe a local artist wants to do an art instillation and you can get some cool rare statues. Maybe as you build a habitat you can petition for sponsors! So local companies can support your habitat. Like imagine a “Pipshot Water” sea lion habitat. I think it would be cool.