Having enclosures larger than what is needed is simply unnecessary and while sometimes nice can actually harm some species.
Yes I believe some animals should have smaller habitats but an enclosure for a elephant herd for example should probably be around the size of the Fort Worth Zoos new Elephant Springs expansion.
Yeah, I know a lot of people wanted the sea lion over the grey seal, but I'm glad we got the latter because it has that regional diversity. (I assume that people asking for sea lions are specifying California sea lions) African rhino species are easily one of the most requested. It's safe to assume that we'll get one in a DLC pack at some point. Leopards are a pretty common request too, though a bit contested, some folks feel like there are enough big cats. Now that we know they can do semi-aquatic species, a LOT of people want sea lions. A lot of people were disappointed that the Australia pack didn't include Tasmanian devils. Clouded leopards are another request I see a lot. A lot of people also want full aquarium and aviary additions, although I don't know which species are the most wanted.
I hope that we will get a free aviary and aquarium update if we ever get one or both. Frontier is known to give free updates with dlcs, so we might have the aviary/aquarium for free with few free species and then a DLC with animals that can be used in one of the 2 particular enclosure. I see people complaining about their marketing model, but you can't complain until the extra stuff is more than the free stuff.
That's their general pattern. New gameplay features are part of free updates while the DLC packs just include new scenery and animals. (or in the case of Planet Coaster, rides) I really love this model because it allows the DLC packs to include new animals that can use those features, rather than just relegating those species to the one DLC pack that you have to buy to get the feature. That was something that miffed me a little bit about Zoo Tycoon, since the aquarium tanks were exclusive to the aquarium DLC, the other DLC packs couldn't include new tank animals. It would have been really cool to get some tank species in the extinct animals pack, or the endangered species pack.
The original Zoo Tycoon included special animals before the release of expansion packs. If they decided to add some more unusual creatures to the game this is what I envision. Prehistoric Pack Woolly Mammoth, Saber-Tooth Cat, Dodo, Megatherium and Beelzebufo as an exhibit animal. Jurassic Pack Tyrannosaurus, Triceratops, Stegosaurus, Apatosaurus and Compsognathus as an exhibit animal Cryptid Pack Unicorn, Yeti, Chupacabra, Mermaid and the Mongolian Death Worm as an exhibit animal Of course I doubt these could ever happen but we all know that if something like this ever did happen, it would be the most downloaded packs in the game's history.
Given Frontier also is the creator of Jurassic World: Evolution, anything prehistoric is almost given to not arrive in Planet Zoo.
My animal textures are no good, but the rest of the game works and looks fine. I've heard that some graphics cards have had issues with that
Adult elephant has too low-res texture even with high graphic settings. And no bump map, looks like it was made in a hurry.
I wonder if devs would let animals eat foliage & grass in future. Zoo Tycoon 2 and Wildlife Park 2 had this feature (as well as egg laying).