Wetlands could've been so much better as a mermaid
Alright, here's the kick: Lately, I've been on a binge on Chinese dramas and mythologies and when I came acrossbthe jiaoren (Chinese mermaids), it made me look back at Weilan in MM and while I didn’t dislike her and more knowledgeable on the fact they could have done her character not just better in how a pod of mermaids was living on land in China (with a big emphasis on where exactly they were located and how many), but also that even if they kept the golden tail, her powers shouldn't been tied to the lore of a Chinese mermaid.
Like for starters, having her cry pearls as tears. That's a big part of the jiaoren mythos and could have been expanded. Then there's the mermaid silk making (water proof cloth that emphasizes elemental weaving skills - not a bad hobby to have far from home as a trait). And maybe the water dragon being a more water-curated variant of a jialong and if real Chinese dragons exists?!