With the direction Frontier is going with the animatronic animals in the game, plus their Planet Safari project I doubt we'll see any animal-like Expansion/DLC. But I could be completely wrong on that note.
But I do think adding more animal animatronics in future DLC and Expansions would be a gread addition. I've seen some creators use the animal animatronics we have now to create zoo-like exhibits/galleries. The same probably goes with Jurassic World Evolution so adding dinosaurs into the game probably won't be a reality for Planet Coaster, but more on the lines of dinosaur animatronics could be a possibility in the near/late future of PC.
Maybe incorporating more animal animatronics would not only create a work-around, but also eliminate the need for a RCT3 Wild Expansion so PC could focus on more amusement park elements and gameplay features. So for example, if PC released a Circus/Carnival themed DLC they could also release animal animatronics like elephants, lions, tigers, and bears. A Western themed DLC could add horses, buffalo/bisons and cows, along with some birds of prey like vultures and hawks. And a marine-themed DLC or Water-themed EP could incorporate sharks, whales, dolphins, animated coral reefs or even the ability to create aquarium-attractions. So there is a work-around depending on the theme and what animal species they could incorporate into the pack.