Not that I inherently disagree, but they did just announce that Sword and Shield will have a vastly reduced number of obtainable Pok?mon.
Of course those two games aren't that comparable because AC reuses the same species' models and doesn't require nearly as many separate animations, but there could always be other reasons to cut numbers/features.
I agree that there's no reason to worry much though, and especially none to assume it'll inevitably happen.
If anything I'd be more concerned that they won't add enough new animals, or barely expand on their dialogue and behavior.
I wouldn't go ahead and compare this with Sword and Shield. The Sword and Shield problem is kinda
more complicated, as GameFreak doesn't even care to look for the option to add the missing Pokemon
via updates or DLCs in the future to the games, which fans doesn't understand of how stubborn they
are. So, even if not all villagers are available at the beginning, they could always add them later with
updates or DLCs and I'm pretty sure the creators of AC would use this option and aren't as stubborn
as GameFreak.
Alternative, it could also be that Switch can handle all villagers and they are all here from the start.
After all, the game got delayed because they want to make it the best and I'm sure they taking also
care of the villagers.
As for the amiibo situation, I would be kinda sad if the special villagers stay New Leaf exclusive. As
for now, I think they will coming back. Otherwise, I will just wait till they explain it more in detail of
how you can use amiibos now in this game.