I'm glad the space requirements will come down but let's face it, it was a bad choice to have it so high to begin with. Polar bears live longer in captivity than in the wild by a large margin so the 'small' zoos must be doing something right. A zoo can never give any animal the space it has in the wild. A tiny meerkat needs well over 1km of space for their natural habitat! I've never seen a zoo give a meerkat such space! Because in reality animals don't actually 'NEED' the space, they just need in the wild to find enough food and shelter. With zoo's it is less about space and more about enrichment and keeping minds active and encouraging new behavior and exercise.
If you want to make it harder to keep polar bears, why didn't you include some special enrichment for them? It wouldn't have been time consuming to basically re-skin the dirt forage box enrichment into a snow/ice forager. (Maybe it melts if the temp is too hot) This is what happens in real life zoos, they bring in big piles of ice/snow into the enclosure (because most zoos don't keep polar bears on ice, but instead dirt and rock) and hide the food around inside the snow to encourage natural behavior. Also piles of snow could have been an enrichment item. The bears play and rub around in the piles of snow which could have had nice animation to go with it. Zoos have 'iceberg floaties' which are just tough plastic toy in the shape of a white iceburg the bears can push around and play with in the water. Zoos bring in live fish enrichment in the water to encourage natural hunting and exercise. You could have created a new 'underwater rock' forager that is placed in water and the polar bears have to dive to reach it. This would have been a nice compromise to make the bears more realistic in that they would dive underwater without 'really' having to code actual diving mechanic. Having this rock forager right by an underwater viewing window and the bears diving in front of it would have been awesome.
If you want to make them harder to keep as well, polar bears actually have a high mortality rate for cubs - both in the wild and captivity. This could have been included in some way, like more susceptible to get sick and die quickly as a cub if not treated effectively. Maybe only a vet with 5 stars could look after a baby polar bear that gets sick.
If you want to go into realism regarding good zoos/bad zoos, you could incorporate a stereotypy mechanic into the actual game. If the animal is not receiving all it's needs particularly with space and enrichment, the animals could develop stereotypical behavior (pacing back and forth, head swaying), which give guests negative emotions.
