@Thomas
Here are my personal thoughts and opinions
I think those species that require new models and animations should be prior since they cannot be done well by the Modders, like Tree Kangaroo, Black Howler, Spider Monkey. While those copy&paste species (like second Giraffe species) can just use Mod version.
This map from the Frontier forum shows the distribution of current species over the world. We can see several regions still have lack of species like Patagonia, New Guinea, Caribbean, Philippine, etc. So I think Patagonia Mara, Tree Kangaroo and Roseate Spoonbill are great additions.
I also like the rosters to be as diverse as possible, so I would welcome more birds and habitat Poikilotherm.
Here is my wishlist:
Tree Kangaroo (one of Goodfellow or Matschie is fine, I personally prefer Matschie): although the Modders have done 3 species of Tree Kangaroo, none of them are decent and realistic b/c there is no perfect match of models in the game.
Black Howler: the Mod of Black Howler has weird face, probably b/c it is hard to work on furry faces of Primates, which requires a lot of details. Also the Black Howler has howling animation and sound that is different than other monkeys in the game.
Geoffrey's Spider Monkey: the Yucatan Spider Monkey is the only Spider Monkey species offered by the Modder currently, it is modified from Capuchin's model. The appearance is fine, but the animations that include swinging and prehensile tail movement, cannot be done by the Modders. Someone asked the Modder whether should use Gibbon's model instead, but the Modder said not quite sure, we know Gibbons doesn't have tail, still not that matchable (also Gibbons walk by two feet, Spider Monkeys walk by four feet, that is also different)
Northern Luzon Giant Cloud Rat: this giant rat can represent Philippine fauna, compare to most Rats they are large enough as habitat species, and they have same color pattern as Giant Panda. The Mod one uses the model of Meerkat (Prairie Dog also uses the Meerkat's model), they have totally different behaviors since Meerkats are ground and cave-dwelling, while the Giant Cloud Rat is arboreal, so the Mod one cannot climb, which couldn't match with the real-life behavior.
Patagonian Mara: the essential species of Patagonia
Coati (either South American or White-nosed is fine): the most demanded species in Frontier Forum, and we definitively need more Latin American species.
Victoria Crowned Pigeon: this large Pigeon is well-known for its elegant plume crest, unfortunately the Modders couldn't do the good job on the crest, probably only Frontier can work for that. I think this bird is a great addition b/c it is beautiful, common in real-life captivity (good for zoo replicators), and would be the first Pigeon species in the game. They spend most of time on the ground, and large enough as habitat species, so they are definitively the most appropriate Pigeon to be added to the game. Also, they enrich the Oceania and New Guinea theme.
Golden Snub-nosed Monkey: This might be the niche choice in Western players' view, but China is the country with the largest number of PZ players (about 21% of PZ players from China). The golden snub-nosed monkey is an essential species of Chinese theme and the most demanded species among Chinese PZ players. GSN Monkey is also endangered species with successful conservation. The Mod one is modified from Proboscis Monkey's model, but not realistic enough due to incorrect overhead and lack of long mantles at the back (GSN Monkeys especially adult males grow long mantles to cope with harsh winter in their natural habitat).
Lion-tailed Macaque: this unique-looking monkey could represent the South Asian primates, which we don't have in the game yet.
Sea Otter: this popular, adorable and playful species requires several unique animations including tool-using and hugging babies during sleep. So I hope the Frontier offers Sea Otter. Worth mentioning It has strong conservatory value
Short-beaked Echidna: a great addition of Oceania fauna that satisfies both Australia and New Guinea theme.
Blackbuck: although it is copy & paste species, I would welcome that b/c it represents South Asian antelopes
Honey Badger: this active and playful Mustelid is well-known for its fearlessness. Would be an interesting addition for not only African but also Middle East and South Asian themes.
Green Sea Turtle: I would welcome the Green Sea Turtle for two reasons: 1. fill the vacancy of water Turtle as habitat species; 2. would be the first true open ocean species
Coconut Crab: it is interesting to have the first invertebrate as habitat species.
Walrus: great addition to Arctic theme
Shoebill: the magnificent bird that known as "living T-Rex", although the Modders already did a good job on making it, I still want the Frontier to offer b/c it is my personal favorite bird.
Secretary Bird: one of the most demanded species, and would be the first Bird-of-Prey if added to the game.
Great Bustard: another niche choice, this bird can be used for variety of themes including Europe, Mediterranean, Middle East, Central Asia, Siberia and East Asia. The males show beautiful plumes during courtship, which requires detail work on animation. The Modders do not offer this species yet.
Roseate Spoonbill: a beautiful bird that can be used for many New World themes, and would become the first Caribbean species.
Red-and-white Giant Flying Squirrel: Having some gliding species for walkthrough exhibit would be interesting. This species is beautiful, adorable and big enough (easily found in the exhibit). The Mod one is made as habitat species, but unfortunately it couldn't glide.