"very very slight improvements"
The series has changed. It's not aimless enough to support everyone having the exact same experience in one town anymore. It has a story now, and that story is for one person only.
You cannot all be mayor. You cannot all have control. There is a zero-sum decision to be made in all this, and ending sharing a town is the sacrifice that would solve all of the other complications:
- each account would have discrete saves for NSO cloud backups
- each account would have their own private sandbox with absolute power
- progression would revolve around a singular person, so everyone gets the same experience
You're asking for improvement without compromise. There is an obvious path they didn't take due to their attachment to the series's history of sharing towns, but people are angry enough that they'll take it in future entries.
The real question here is if it's even technologically feasible to overhaul how saves work for this game and switch to this solution with a patch.
Compromise is exactly what I'm asking for.
I understood the cloud save issue.
I understood the online restrictions.
I understood the single-island per console.
All of this with the assumption that sharing an island, which is what Nintendo is encouraging, would not be a reduced experience if shared with more than one person. I don't think this is an unfair assumption.
Looking at the other comments throughout the internet, even in this thread alone, you'll see that sharing a village in Animal Crossing has been a major part of the player experience. It's one of the things that people love about the game and one of the benefits of it returning to consoles. Nintendo talked up sharing a village with other profiles in their Direct but as you admit, they did not warn of any gameplay downgrades for the other players.
Is it really so surprising that family members and significant others are sad that they cannot share the full experience together? That they're surprised and let down?
I'd love some sort of compromise to be included. I think letting multiple villagers participate in island projects should be fair but if it's not, then let me relinquish that title to my girlfriend. She can take over.
Even if you think Animal Crossing is, or should, change to become a single-person experience, I think it's fair to say that they should have warned players that these changes were coming. The fact that they didn't is what led to the shock and upset reactions that we're seeing everywhere today.