Hey constant, yes I'm back from vacation (sorry), and I've read your article. I do agree with most of your takes, like the npub being an identifier vs your identity.
I would also argue like Gigi that identity is not one, it's prismatic and multiple. For some people I am "the neighbour", the "brother of X", and for many even the "idiot" :)
Anyway, it's a nice idea doing these associations with Musig (should be possible but I've never used it). Instead of a Twitter-style unilateral follow, it's more like a Facebook-style friendship.
I'm always skeptical because imo one should start with what people are doing, and then analyse the behaviour to extract insights, not by creating a new type of interaction and then go out and convince people/apps to implement it.
Don't get me wrong, it would be a cool experiment, just not personally interested in doing it because fundamentally it would require to bootstrap a new network effect of people using these interactions for some reasons (which ones?), and then keeping them updated over time.
This is the reason kind 3 akak follow list is so dominant compared to follow sets and similar. Everyone uses it, there is a lot of data, people keep it cheated and updated over time, so it mantians its signal despite the natural entropy.