More Nintendo themed items! I really enjoyed the Nintendo theme items from Gamecube Animal Crossing. And the Mario theme was fun in New Horizons. I wish they would expand on this more. Do an entire Pokemon theme with a bunch of plushies. Or do entire furniture sets for Zelda or Metroid or whatever so you can make a themed room in your house entirely based on your favorite series.
They had 15. I read somwhere that they were able to have more villagers because part of your village that you weren't in was in "sleep mode", things weren't happening, villagers weren't moving or doing things, until you came into that sector of you village. So ACNH is a little more dynamic, in that villagers come to your house or do events by village hall, but the tradeoff is less villagers. I feel like Switch (or Switch 2) should be more than powerful enough to handle a few more NPCs though