We just recently had a big thread about problems with ActivityPub, so in some ways I guess we’re already thinking about it? 
Personally, with the issues I’ve learned about ActivityPub and from what I’ve gathered that other people have talked about, it really seems like AP is ripe for a 2.0, or a spiritual successor, and this is while not even considering the SWF. The way the SWF is talking about AP 1.0 just makes me want to “fork”, if I can even use that term. These motivations are compounding.
Are there any existing promising protocols out there that could satisfy/fix the issues we’re seeing? Ideally while simultaneously not being too different from ActivityPub so that a potential migration would be feasible? I honestly don’t know the ecosystem out there. It’s very tempting to just try writing a new protocol obviously…
Leaf sounds interesting but perhaps too complicated for this use-case? Willow seems to be a very general thing, but I think we can be more specific (and therefore simpler) when we know that we want to constrain ourselves to whatever the “social web” means.
Veilid sounds very technical - can this be user friendly enough? I’ve tried getting software engineer friends to sign up for Matrix and even that was difficult!
I would not trust Bluesky or any other centralized entity to be the future of the fediverse, especially not a profit-based one.