I'm loving ACNH for the most part. There's a lot to do, especially since I love the town planning aspect of Animal Crossing. I'm not disappointed at all. That doesn't mean it's free from criticism though...
Number one complaint: LACK OF TOUCHSCREEN SUPPORT! I play handheld only, and while these controls make sense for docked play, there's no reason why I shouldn't be able to use the touchscreen for menus and such. It's annoying to organize pocket space, for example. If I want to rearrange stuff I have to push A and hold, it seems so sluggish! Why doesn't "pick up" show up in the menu like other games, just stuff like "place object" or "drop"? It's almost faster to reorganize stuff by throwing it on the ground and picking it back up. The placement for the options is different too, it's annoying that it defaults to "drop" instead of like, "eat" when you have a fruit selected. You know how in Stardew Valley when you have spaces in your inventory, and you can press a button to reorganize it? That's what we need, at least. People aren't going to be playing this game exclusively docked, a lot of people are going to play it in handheld, especially since the Lite is out and they don't have a choice.
Making designs is a pain. It's almost like they WANT you to use the phone app just to scan QR codes. I used to love making my own custom patterns in ACNL but I don't know how often I'm going to be doing it in NH. WHY can't there be touchscreen support for this? Why can you draw properly on the bulletin board of all things, but NOT on the more important feature? Maybe there's something to be said about making pixel art, but as someone who makes pixel art, this is SO tedious and slow. It's more efficient to use a stylus, and have the other controls as an option for people who prefer those. Switching between the canvas, colours, and tools is torture. No zoom-in option, either.
And customizing furniture... or lack thereof? In NL you could change a majority of furniture but in NH it seems like you can't change ANYTHING you buy at Nook's Cranny. Tom Nook even said that "something something you can change some of the mass-prthings the store sells something something", but I haven't found a single non-crafted furniture item that's customizable, and it's annoying. Why the limitation? To promote trading?
Also something I don't hear anyone talk about (or maybe I'm looking in the wrong places), KK Slider? Why are they using the same soundfont (?) over and over and over again? All the animals have fresh new voices, including KK himself, but when he starts singing it's the same voice he's had for nearly 20 years! At first I wished there was an update for the airchecks, not making them MIDIs. Or maybe, making them better MIDIs. There's a certain charm to it, I guess, but it's also 2020, you know? But then I thought about the live performances... that's even worse! KK Slider's voice isn't a "omg this game sucks and is bad now" thing but is something I'm going to choose to nitpick! If they can update the animalese in each game, why leave his singing the same?
The new NPCs and characters. They grew on me, I like Flick and CJ and Daisy Mae. I liked them when I first saw them, too. But looking at them, cynically, they feel like they were designed to sell merchandise. People LOVE Flick and drew fanart of him as quickly as possible, but how many people gush about Nat? Would the mainstream audience rather buy merchandise of Nat, or of Flick... Joan, or Daisy Mae? Same with the other new villagers added, Raymond, Audie, etc. There's like... a formulaic feel to them. They were DESIGNED for people to love them, so they could be merchandisable. They feel like Marshall, Julian, Stiches, and Merengue— villagers the mainstream will go nuts over. And they succeeded. I like the horse (don't know her name yet) but the rest made me go "ugh, this again?". I don't necessarily like "ugly" villagers but they have personality at least. These guys just scream "Please sell me on eBay for lots of money!" and "I'm going to be on everyone's villager wishlist until the end of time!". Between the character design and the "too nice-ness" of NL and NH, this seems to be something Nintendo wants to continue with, unfortunately. Objectively I guess there's nothing wrong with it and new players probably won't miss anything, but as someone who has played AC for a long time, it's disappointing. The quirkiness of the old games is dropped in favour of safe, fluffy niceness.
Other missing things like Brewster, gyroids, etc. are bothersome too, but I would think these would be added in a later update. I can look past that, for now at least. Things like the villagers personalities won't change, but things like touchscreen support and potential pocket fixes could be added in an update. I'm not sure how likely it is but I'll remain optimistic.
People have mentioned bugs and glitches, but I haven't experienced any myself. They should look into fixing that duplication glitch ASAP, though. And I thought the music felt a little repetitive too but I thought it was just me playing the game too much, haha. My other complaints include the lack of personality the villagers have, but NL had that going for it too and I didn't expect it to change here. I was never big on online play, but I wish there was something else to do. The island in NL was a lot of fun.
Skimming through the thread before posting this, I seem to be more thorough with my complaints than most, oof. I like to go into detail with these things though, maybe someone might actually read it! Lol I'm sure I'll think of more things as I'm playing the game but for now I'll leave you with this.