So, my thoughts on the wetlands DLC's animal choices, from least to most;
Spectacled caiman: even an absolute crocodile fanatic like me has to admit that... We didn't need another croc. A large freshwater turtle, like an alligator snapping turtle or a Malaysian painted turtle, or even some Southeast Asian softshell turtle, would be a way better choice. And if it has to be a croc, something like a Cuban crocodile or a slender-snouted crocodile, or even a broad-snouted caiman would have been better.
Nile lechwe: I feel that the nyala already fills the quota of an African wetland antelope; I would have much rather had the Pere David's deer or the Chinese water deer, or hell, how about the South American marsh deer?! I'd have even preferred the blackbuck, to make mixed exhibits with the Indian rhino, but they aren't wetlands animals, are they...?
Asian water buffalo: I'm not that bothered about this one; domestic Ungulates aren't an unknown in the game, and it's a neat contrast. Still, I would have preferred the gaur, banteng or forest buffalo.
Asian small-clawed otter: Ah yes, aquatic meerkat... All jokes aside, I actually think it's a solid choice; the smallest otter species contrasts wonderfully against the largest (in length), and it's a very realistic choice for this game.
Capybara: This animal was nigh inevitable, and I'm very glad this absolute staple of tropical South America has finally made it into the game. It will work wonders for mixed exhibits, and I sure hope they took that into account.
Red-crowned crane: FINALLY!! Another bird! Waders and waterfowl are extremely common in zoos, many of them wing-clipped, so the flying animal mechanic needn't be a limitation. This crane is an excellent first dive into this group of animals; now I'm just pining for Swans, pelicans and ducks to show up too.
Platypus: an animal I never would have expected to see in this game, I couldn't be happier to see this amazingly rare monotreme represented in the game. More Australian animals can only be a good thing, and you can't get any more Australian and frankly amazing than the platypus. Well done frontier! I can't wait to build a habitat for them!
Now I'm just left to speculatie on what DLC's may appear in the future... Madagascar, greater Asia, arboreal animals, aviaries... Sky's the limit!