Your Feature Request / Idea
If the title hasn't given the general idea behind this thread, I am writing to suggest something a lot of us experienced management sim vets and masochists alike would very much enjoy.. An increased difficulty setting for the main campaign which will be the same as before but with Jurassic challenge level parameters including the Hammond Foundation fee and a new Declining Guest Interest mechanic.

To start, ill explain what I mean by declining guest interest. It is pretty simple, after a while of having the same dinosaurs roaming your park, eventually the guests will begin to grow bored of the current species on display and start coming to visit less and less until the parks attendance is a paltry 25% of it's highest guest attendance record. Both modelling the same issue faced by Clair in Jurassic world and adding another MUCH needed layer of management someone will have to keep in mind while building and managing their park.

This wont start until a certain honeymoon period after introducing a new dinosaur species to the park has passed, with the length of the honeymoon period being determined by both the number of the new dinosaurs introduced multiplied by the actual base rating of the dino. If the new dino is replacing an old already recognized species, then the old species will go through a long cooldown before a new reintroduction will have a full honeymoon period. This of course can be bypassed long as the returning dino is at least a 25% authenticity increase since its last appearance. That way if you remove a species that didn't have a full genome and immediately reintroduce it with at least a 25% improvement you can use this as a nice quick boost in case you've exhausted your new dino options with just a quarter of a star left to go for the next rating and your guests interest is starting to wane.

However, if you introduce more than 3 species at a time then the honeymoon period will be cut in half for every extra dino added until the previous honeymoon period has ended. So planning out your expansions and spreading out new exhibits over time will maximize your peak post reveal attendance far better on your gradual climb to 5 stars. But for the sake of early game balance, the first honeymoon period after releasing your first dino will be a fixed, and very long period of full attendance to both give you an opening breather and simulate the wow factor of the first dinosaur being cloned and put up for show to the world to see as it would likely be a world shaking spectacle the first time.

I think a mechanic like this would model what many actual amusement parks and zoos are faced with in the real world both increasing immersion and giving another layer of challenge for those who have drained what little challenge they could get out the game and want more. Plus helping to remedy the insane profit snowball that literally every mode of gameplay is plagued with except for Jurassic Challenge mode, and even then after a while the same profit snowball rears it's ugly head despite the very haigh hammond foundation fees. This would force you to keep expanding and planning out your park alongside species rotations or risk letting your park fall out of interest with public by not changing up the sameold same old every now and then.

This of course isn't the only thing I would really like to see, but I would also really like it if both this new mechanic as well as the difficulty parameters offered by the highest challenge mode difficulty be given to the campaign once a player beats the main campaign on the vanilla difficulty as a new mode. This would give the game more replay value and let someone who thinks they are well grounded in the management of a Jurassic park to try and give the campaign another go with what they learned in the first, easy playthrough at a difficulty that they atm can only experience in the challenge mode, now applied to the exact same maps and challenges in the main campaign.

The new mechanic would of course be able to be shut off if the player doesn't want the publics interest to be a constant matter of concern, but i'd at least say a new achievement should be added for those players that do play and beat both the challenge mode and harder campaign mode thats maybe called something along the lines of "Who in Gods name do you think you are? John Hammond"