Something like that! Probably would have to be a lot simpler than attestr.
Another approach I am partial to is nostr:npub1u5njm6g5h5cpw4wy8xugu62e5s7f6fnysv0sj0z3a8rengt2zqhsxrldq3 's decentralized lists for this kind of thing:
https://nostrhub.io/naddr1qvzqqqrcvypzpef89h53f0fsza2ugwdc3e54nfpun5nxfqclpy79r6w8nxsk5yp0qyt8wumn8ghj7un9d3shjtnswf5k6ctv9ehx2aqqzdjx2cm9de68yctvd9ax2epdd35hxarnwrn9hx
https://github.com/PrettyGoodFreedomTech/nips/blob/decentralized-lists/93.md
A list like "good comedy movies in 2025" that people can contribute to, then using GrapeRank WoT you could not only filter out spam, but filter the list based on contextual reputation, like "only show me npubs' contributions if I trust them for comedy movies" or "show me npubs' contributions whose taste in movies I **strongly disagree with**" (so you know what movies to avoid).
Even if 8 million npubs contributed to this open, decentralized list, you don't have to give a shit about most of them except the people in your GrapeRank AND the trust-context you care about - handily cutting the whole human populations' opinions down to a handful you can actually make sense of.