I want the ability to find out who wants to move, maybe from town hall. For example you could ask isabelle if anyone is planning to move and she would say something like "Yes! Wolfgang gave his 10 day notice on the 17th".
I also want to be able to tell a villager where they can/can't put their house.
I'd like to grow vegetables! Like corn, squash, peas, zucchini, pumpkins, carrots, etc. And watermelons, cantaloupes. I'd also like new fruit, like plums, apricots, pineapples, kiwis, avocados, papayas and maybe even hybrid fruits, like the apricot x plum hybrids. I LOVE growing things, both on acnl and irl.
Oh, and the ability to make stuff from the things you grow. Bring cyrus a pumpkin and maybe a pie plate, and you get a pumpkin pie in return that you can display (or eat/give to a villager as a treat) or an apple and pie plate, and you get an apple pie, things like that. Or even a kitchen of your own where you can make things with recipes!
If this was implemented, maybe villagers could ask you for a snack, and not specifically ask for a piece of fruit. This would also give the existing cake, cider, lollipop and candy items a new purpose. Villager treats. <3
The ability to build something like a hydroponics room would be amazing too. I'd love to grow flowers indoors!
I would also like a plant section in the museum. One of every kind of rose, violet, etc. Perhaps an outdoor botanical exhibit would be awesome for different types of trees and bushes!
On the subject of the museum, a section for reptiles and amphibians would be cool too. I'd love to go hunting for little lizards, salamanders, frogs, snakes, turtles, etc. (I realize there is already a frog and turtle in acnl but they're categorized under "fish" and that just burns my biscuits)
I'd absolutely like the ability to change skin tone. I'm fine with the palest tone, since I'm pale myself, but it would certainly be nice for other people! I'd also like for tanning to be totally removed.
Honestly, I'd love the ability to just set up my character from the beginning. Pick my eye style, color, hair color, etc. I don't really want to just freely pick my hairstyles wherever because I don't want shampoodle to disappear, but I'd love to be able to browse maybe.. a hairstyle catalog. A little book that shows all the available styles she can do, and you could tell her you want "this" style. None of this "look up a guide to pick the right speech sequence" stuff.
I'd also like for villagers to wear something other than shirts. It would be cute for them to wear dresses, long sleeved clothes, hats, shoes, etc.
It would also be amazing to be able to change their flooring and wallpaper.
Oh, and I would LOVE to be able to turn off their music when I walk in, like their TVs. I hate their songs sometimes. xD
I would also like more character development for villagers. Maybe even make a new personality, like "shy". They start off skittish and shy, perhaps very short speech and very generic phrases commenting about the weather, and then as they get to know you and trust you they start talking more and more, kind of like Mabel.
I would also like to be able to use more than 10 custom designs at once! >.< My creativity doesn't like to be limited to just 10. xD