I agree with many of these suggestions, especially a skin tone choice and the ability to rotate PWPs. Snakes, and other reptiles, would be a great addition to the museum.
Here are some of my own that have been bugging me lately:
- No risk of getting an unwanted villager from the void
- Make grass wear optional
- More control over villagers in general. Choose where they plot their house, kick them out at will.
- Really minor, but... make villagers stop spontaneously change shirts with each other. Or at least make it easy to get them back into their original outfit.