I don't really feel the need to repeat the obvious stuff that has already been stated so much already. What I will ask for is some other more incidental things that maybe are not so critically important but would be fun and entertaining to me and make long-term playing a bit more interesting.
1. Failure animations: Mainly for dinosaurs, basically additional outcomes to certain actions in the form of fumbling. Like imagine a dinosaur chasing down someone and they end up tripping on accident, or they bite or grab someone and end up dropping them before doing any real harm. Maybe they can just lose interest, or even play around with a body, like imagine an indominus rex picking someone up, and just walking around with them and not eating them for whatever reason.
2. Intelligent dinos requiring enrichment: If you know how real world animals behave, particularly smarter ones like primates and some varieties of bird, a general rule is that the smarter it is the faster it becomes bored, the faster it starts making trouble to entertain itself. So dinos like the raptors, indominus rex, and indoraptor could have an extra layer to maintaining their comfort, likely in the form of a variety of "toys" or other amusements and contraptions (for example, having a food dispenser/container that requires solving a puzzle of sorts in order to acquire the food), maybe hiring trainers like Owen Grady to interact with raptors and indoraptor, that sort of thing.
3. Additional dino behaviors: Mostly differenciating AI and behaviors unique to specific dinos, as an example having the spinosaurus or similar dinosaurs be able to wade in somewhat deeper bodies of water, indominus rex using its camo, indoraptor pretending to be tranqed and generally acting a bit more cheeky than one expects out of a dinosaur, etc.
4. Randomized AI "personalities": I think it would add huge replayability and entertainment if distinct behaviors and habits can appear with dinos that act as a modifier to the base Ai behavior. It'd be the sort of thing that makes players go over and actively follow specific individuals just to see what they are up to, and be able to recognize individuals just from a slightly off or specific behavior or reaction. For example, a normally social type of dinosaur being kind of distant, a dinosaur being afraid of cameras, or being remarkably interested in following around people, a carnivore who wants to eat more due to being sort of a glutton, etc.
5. Permanent scarring/injuries/status: A dinosaur who has fought so many times and been injured in the exchanges could develop scars, as well if it's been severely injured there could be a chance of a permanent limp, stuff like that. Older dinos could have their eye and scale color fade over time, maybe exhibit blindness or general slowness as they get older as a contextual/visual indicator of death approaching, but obviously with enough variance that you can't predict it.
6. Fighting expertise: A dinosaur that has survived consecutive battles could be made faster and deadlier, as well as more evasive against enemies in combat. Show that they are becoming more adept and experienced at defending themselves and killing enemies instead of it just being a number.
7. Birthdays: Have the ability to arrange a birthday celebration for certain dinosaurs (up to the player). it would be something you set and it ends up automatically happening. Most older, or particularly impressive/loved animals at zoos tend to get the birthday treatment. I can see it being a fun thing that will attract the guests' attentions and allow you to treat a specific dino for that special day.
8. Dinosaur age: This has already been said before, but in order for most of the stuff I am proposing to be worthwhile dinosaurs really do need to live longer. Make it less about constantly replacing them, more about keeping and treating them well. Maybe make exemplary conditions and happiness significantly improve their lifespan, while being stressed or otherwise unhappy reduces it.
9. In synergy with the other suggestions, it may be neat to be able to dedicate a statue or other thing to a particularly loved or memorable dino who died as a way to immortalize them, and you could write like a simple paragraph or few sentences for them.
