(3) One big benefit of #MastodonWorld was that folks could have a 'landing pad' to then move to another instance. It might be worth it to have that sorting element, of finding their next instance or server, be brought into some form of ongoing inter-server #fediverse relationship building.
(4) I see you've launched the pool-appreciators instance... I think a very strong argument can be made to also create spin-off instances that naturally flow from #MastodonWorld and support point 3.