I also agree with more dialogue options/variations with villagers (maybe even some unique dialogue for particular villagers, even if it's just one or two things one villager will say that another of the same type won't) as well as villager zoning. I don't see why the former can't at least be added as DLC.
I also agree with more customization of the mayor/playable character, more events, and different terrain (villages based in a desert, a swamp, a jungle, lagoon, forest, etc).
Other things...welp, it's more of what I'd like taken OUT of the game, with a couple things to add:
-Get rid of the Void
Seriously, when has this been a good thing? I don't want someone's voided villager if I have less than 10 villagers in my town!
-Get rid of the 16 villager cycle if you accidentally lose a villager
I've still got another 12 villagers to move out before I can get Purrl (who never pinged me to tell me she was moving, but was fine pinging me to ask for fish or to deliver something) back in. I've been trying to get a 5th out for the past day and a half, nearly 2 days.
I don't know what the point of the 16 villager cycle is in the game, except that it's as annoying as ****
-Allow the player to talk a boxed villager into staying
Again, Purrl never told me she was moving, and nobody else said a word, either. I only found out when I loaded up the game and Isabelle told me she was moving out.
-More things to do with the beach
Cause really, all that can be done is planting flowers and trees on it, or laying down patterns...or just scattering items or seashells everywhere. It'd be really cool if a player can put their house on the beach, or there are beach-specific PWPs.
-Ability to design pants/shorts
Self-explanatory.
-A different way of catching fish
The only challenge is the timing of hooking the fish. Once you hooked it, you'll automatically reel it in. Frankly, fishing is quite boring, especially once you've caught every seasonal fish available. I'd love to see a minigame with fishing similar to fishing games like Fishing Resort...or at least close to what either Mabinogi or Fantasy Life has.
-More minigames/quests
Sure, you can play minigames on the island, but they're the same things: fishing, bug catching, diving, searching, or digging. Yes, the memory game adds some variation, and there are difficulty levels, but I'd like to see minigames besides events/holidays or the random hide-and-seek game in the town itself.
Some bigger and better quests besides "can you deliver this package to that villager" or "I want a river fish", or the famous "get me some fruit" would be nice.
-A different way to unlock PWPs
Because it's frustrating when you're two PWPs away from completing the look of your town, and the only thing your villagers want of you are mundane errands or new catchphrases (even with the diving trick).
-Haggling with villagers
I know there are times when you can get an item's price lowered for something the villager is trying to sell you after pinging you, but that only seems to apply if your friendship is high enough. However, I haven't really seen any option to haggle if they want to buy something I'm carrying. If they're ripping me off (offering a lower price than I'd get just selling it at a fourth of its value at Re-Tail), I want to jack up the price, not cancel the transaction completely.
-Starting out with only one or two villagers and next to nothing, and having to build up the village from scratch.
Many of the Harvest Moon games do this (I'm talking HM before Natsume went solo), and I'd love to see some HM elements in AC. Maybe I don't want to be the mayor, but instead be a farmer or a citizen!
Heck, I'd love an AC/HM crossover game. Why not? Phoenix Wright and Professor Layton got a crossover game, so why not Animal Crossing and Harvest Moon?
Or a fantasy Animal Crossing game! Hey, Rune Factory was a huge hit, so how about a fantasy Animal Crossing where you can go out and battle monsters...or, maybe even a version where you have your own shop and don't have to rely on Re-Tail!