Vey good list. Alot of actual gameplay changes, I like this.I agree with basically everything everyone already listed. So I'll try to list things people haven't mentioned yet.
Everything in Bold is what I consider to be my most wanted or important features.
- Giraffe and Rhino Guest Feeding. Giraffe Feeding being the most important one, it's a key feature in many modern zoos.
- Other animals feedings include Giant Tortoises, Hippos, other ungulates like Zebra and Deer)
- Scratch points. Just like sniff point have certain objects that work as scratch points for animals to rub up against.
- New bedding options. Sleeping rock, sleeping basket, sleeping tree etc. I would love for animals to be able to sleep in more realistic areas.
- Sandbox option to turn off scars
- Flexi Color Paths
- More Water Behaviors. Allow certain animals to splash, play and roll around in shallow water.
- Running Water for creating more realistic streams and rivers
- Not so much a free update thing but please Frontier, more rocks. Jagged cliff rocks, more faux styles, kopje basically anything at this point
- Flexi Color Trees to better depict changing of the seasons
- Rotational Habitat gates. Allow animals to rotate between habitats so it's easier to manage inbreeding, also makes the game more realistic
- Gift Shops and Gift shop pieces
- Sea Lion Show
- Animal Amphitheater, allow certain animals to be taken to a show to educate guests as ambassadors
- Null elevated path
- Different Skyfari ride more akin to something like the one at Oakland Zoo
- Splash Pads for Guests (mainly children)
- Playgrounds
- Null Vista Points, tour points and animal talk points
- New Food options like in Planet Coaster
- Null Waterfalls from Aquatic Pack
- Updated Signs in the style from the past few packs for all the animals
- More Billboard options. Curved, Borderless in all sizes
- More Fonts
- Zoo Map feature (something like a more updated version from ZT2)
- Simpler Trade Center UI
- Terrain Paints like from ZT2 and JWE
- Guest Misters for hot days
- Guest and Animal shades (LideR has an awesome blueprint for this, but building these on your own is very difficult)
- Shade points. Areas where guests and animals will actively seek out shade
- Drinking Fountains for Guests and water bottle refill stations
- 2 in 1 Trash cans where one side is garbage the other is recycling
- More Effects like fire, thinner waterfalls, smaller water splashes, waves, rain, snow, sand blowing
- Strobe lights and lights that mimic lightning
- Blinking Lights, Color Changing Lights
- More foliage that blows in the wind
- Null Benches and Tables
- Events (Weddings, parties, birthday parties, meetings, gatherings etc)
- Smaller Walkthrough Exhibits for Butterflies and the Sloth
- Non Walkthrough variant of the Walkthrough Exhibit
- Greenhouses for feeding animals fresher food. For franchise this could add a tier 4 to food for certain animals.
- Gardeners. New staff type that waters plants and hoses certain things down in the zoo, so aka grounds crew.
- Guest Photo Ops. I see a lot of zoos that ask me if I'd like my picture taken in front of certain things, so why not in PZ?
- Bus or Car tours
- More Natural Enrichment items. Leaf piles, sticks, bones, trees (for rubbing against or eating from)
- Null Enrichment Items. Mud Bath, Hammock, Forager, scratching posts, water jets, etc
- Realistic Sprinklers for gardens
- Keepers hiding animals food. Have certain trees or rocks where a keeper can walk in and hide the animals food for them to find.
- More mother and baby animal interactions (Giant Anteater riding on moms back as an example)
- Staff Vehicles
- Ability to sell baby animals in Sandbox
- Touch Pools
- Animal Bone Tables for guests to examine and learn about (Skulls, Horns, Tusks, Tortoise Shells, etc)
- Movie Theaters (Considering we can already make movies this is more just about the seating areas)
- Climbing Towers for Guests
- Carousel
- Zoo Mascots
- Live Music (Bands playing on stage)
- Moving in the wind Flags for every country
- Selfie Points (Guests can take selfies in front of whatever you want)
- Any new moving Objects. I've heard a lot of people talk about how the game at times can feel static so any new objects that move or adding in a feature that has the ability to rotate pieces on any axis would be great!
- More Map Skirts. City, Beach and Forest come to mind.
- Terrain Selector. (Ability to select desired brushes before going into the map)
- One way paths
- And last but not least, obviously Aviaries and Bird demonstrations.