I think my fear was that something might be built which becomes the defacto standard, and it hasn't been thought through that clearly so we inherit a bunch of technical debt. It's hard because sometimes you don't know till you try, and sometimes it won't happen if you don't try something. e.g. "forks" in ssb threads are a clunky ill-defined ... I hesitate to use the word standard IMO, and we just have to work around that now.
Yeah I'm confident that building this feature will be useful to the fusion identity spec.
I've also imagined that it might be nice to have different "saved views" for collections of identities - like "messages from my family" which is a stream of all new notifications from my bob / alanna / my sister etc. Because sometimes I'm only in the mood for