While I do agree, the following question does come up: why haven't they done the remasters already? And it's not like it's impossible; the tapir and binturong and and hyena and dhole are examples. And even the Bactrian got a size boost. So why haven't they done it now, since that'd really give the game a popularity boost
You have to also remember that the time span between JWE and JWE2 was very small.
Let's assume that the next game is
Planet Coaster 2 for a 2024 release. That's five years since the first game. Comparatively, JWE2 released in 2021, whereas JWE finished in 2019, which is only two years. So again, let's say PC2 gets the same level of support as PC1, so three years. That takes it from 2024 to 2027. At the earliest, PZ2 will be released November 2027, ASSUMING they even do a sequel (a big assumption on top of assumptions already being made here). However, if they spent the five years of development spent on PC2 on a new game engine to allow for whatever changes they want to make from PC1 (higher quality assets, new game modes, perhaps some way of including water rides and proper dark rides and such, all the good stuff) then having that engine already there reduces overall development time for PZ2. So 2027, being charitable, would give Frontier three years to build new assets on the new game engine that already exists.
Honestly, I have no doubt at all that they will reuse PZ1's models as a
base for most animals. Why go to the trouble of remodelling every species from scratch? However, I do believe they will be of higher quality, more individualised (so instead of making the orangutan a red gorilla, we get an orangutan). Plus as we can observe from the newer PZ1 DLC, their ability to make high quality fur textures and shading has massively improved, so that will be another thing to consider. Imagine a lion with a mane that moves like the porcupine quills.
Between JWE and JWE2 there were some improvements made. Nothing groundbreaking, but they were able to add fully aquatic lagoons and aviaries, two concepts people really want for PZ. Water rides were also something deperately wanted for Coaster, as well as dark rides (and PZ players want proper nocturnal houses). All this points to some very obvious improvements in gameplay they can make for a PZ sequel; improved deep diving, godray light blockers, modular aviaries, and so on. Not to mention other things that have long been requested for PZ; animal personalities, model variations, and so on.
As for why they haven't remastered all the previous animals for PZ already; can you even imagine what a massive undertaking that would be? The animals you brought up - binturong, dhole, Malayan tapir - these are fairly minor adjustments made to the existing models. So small they could be made in the window between announcement and release. The tapir obviously was delayed, but even so. The camel got its size scaled up but nothing else about it changed; the model is still rubbish. And in fact they did completely remaster the Nile monitor; they just slapped a new name on the new model and sold it as a new animal (Asian water monitor). For remasters that look good, rely on mods, IMO. They do a good enough job and since they aren't whole new species and all they aren't game-breaking.