They just need to focus some dev resources on signed posts, and the ability to move those signed posts between nodes. That should be their number one priority imho.
I believe that in order to successfully and safely move posts between nodes they need to be immutable and signed. Because you're essentially creating a new history on a new node.
You can't move between nodes, because, unfortunately the usernames in ActivityPub have the server name embedded into them like an email address. Nostr fixes that by having user identity be basically a crypto signature instead.
Which is why you'd need to sign your posts first, so that you can migrate to a new node, use the same key, re-create your old signed history on the new node.
Whichever way they choose to resolve this issue I think it's a major pain point for the fedi to grow.
From an end user standpoint Nostr is way too complex. If we're talking about the fedi being complex, Nostr can forget about it.
But maybe you can prove me wrong. I setup my first fedi node back in 2017 in minutes because there was a container image, people could start signing up immediately. Can you show me how to do the same in Nostr?
Implementation details of an app are what make the difference between "ease of use" or not by end users. That's not a 'protocol issue'. I've implemented both a Fediverse and a Nostr implementation from scratch before, and had them running. I ended up abandoning both for separate reasons. I speak from experience when I say ActivityPub is a nightmare to implement and Nostr is easy.
What Nostr got right is that the core of the system needs to be very simple and be ALL that's REQUIRED to join the network, and with Nostr you're just signing a JSON object with your crypto key and you're DONE. And Nostr objects can live "anywhere" too because the user identity is in no way attached to a DNS name. With ActPub your lovely "Admin" (who might hate you and your politics) becomes your god, because once you build up a following on a specific name, you must bow down to your new god, because they are the TRUE owners of your name.
I believe that in order to successfully and safely move posts between nodes they need to be immutable and signed. Because you're essentially creating a new history on a new node.