Very interesting read!
I don’t see threads.net being very influential in our forum-like slice of the Fediverse
The word you are looking for is "the threadiverse" and no, despite its name (ironic, I know), threads.net isn't really any competition. But this doesn't mean they can't set up ActivityPub scrapers and doing what Meta does best, that being: "The Zucc succ", that's why I'm very wary of them and would discourage any opening towards them until we see some very compelling evidence. It looks like most of the Fediverse shares this opinion of mine.
Additionally, the concept of shared blacklists and some centralized moderation database for instances to subscribe too is ridiculous to consider.
100%. Shared blacklist (or even "greylists") are a good and helpful thing, not everyone can afford to keep tabs on the entire Fediverse to control who they get in bed with, and moving to allowlists would be just sad and likely kill smaller players. On the topic, a great example of how an ActivityPub-wide shared blocklist would be the Fediseer, I'd love to see it get bigger adoption or even inclusion in the protocol itself.