That being said, the new villagers will be totally new, as far as I can tell. Like, friendship won't carry over or anything like that.
If you have a villager move out and then move back a "different" instance of the villager, then, yeah, the villager will be treated as new.
However, if you have someone else adopt the villager and then adopt back that same exact instance of that villager, then they'll actually recognize you and your friendship will stay the same. They'll say something like, "I can't wait to be neighbors again!"
And yeah. I can totally see how some would like this system! I also actually like Peggy in the generic house over her normal one. I guess this comes down to villager interior design in general and being able to change it. I definitely get that lots of people don't want total control, but I think an option would be nice. For example, if you give a gift, villagers already have the, "Hm, where should I put this?" dialogue. I could see an option pop up that says, "I think it would look good here!" or "Good luck!" And I think that having full/a lot of control isn't too unrealistic. People ask for experts to do home design all the time. There's lots of things that system could have to make it feel natural, and it could be optional.
I actually think the current system feels unrealistic in ways. The villagers start in plain homes, which is fine, but then they never upgrade even though the player does. Furthermore, if you're playing AC with friends, comparing villagers is always fun, but the illusion of uniqueness is slightly broken when you realize that the early villagers have the same house, especially if you're used to older AC games. Those are more so the problems I meant since this system is supposed to make things feel natural. :'D