But relays allow me to provide very long lists of pubkeys to filter what I want to see. I can get all from my WoT and work from there.
The influencer asking for global reaction count is so dead-bird-app vibes. Who cares? It will always get spammed no matter what as long as it carries meaning to some people. Don't cater to that vanity metric. Let the influencers brag about their imaginary influence. Nostr as a protocol or its infrastructure shouldn't care about that. Relays should care that they get paid for the bits stored and forwarded. Nothing more.
By elevating the role of the relay I fear we get censorship on a per-relay basis and if client devs get lazy about handling spam from open relays, we might get relay concentration. I know it's not the end of the world as others can always make a more open relay so I'm not fighting your vision but I hope I can convince enough devs to make the alternative happen. Have a flag on requests to limit results to follows of follows so I don't need to upload 10k pubkeys with every request.
Client-side filtering as a secondary barrier does nothing if the relays use standard filter heuristics, blocking what I want not to be filtered.
