I've been trying to put a finger on why I feel different about NH compared to Nl and I think this is why, I think quite a few people (me included) were quite a lot younger/kids when new leaf came out and for many it was their first game that really got them into the series. I'd say for the majority of people playing horizons it isn't their first game hence we kind of already know what's going to happen. Yes Horizons is different but the basic game mechanics are the same so of course it isn't going to have the same charm/excitement as the older games you played when you were younger.You're older that's why. I personally think new horizons game is amazing apart from harvs island.
Animal Crossing is quite a nostalgic game for most people so they might be quite attached to older games, just a personal opinion
It isn't a bad game, we're just older and it takes more for us to get the same excitement about it, plus it was hyped up for two years there is no way you AREN'T going to be disappointed about certain parts of it.