A yes it would make sense for everything you can block/subscribe, but I guess 80% of the value is to "1/4 subscribe" or "4x subscribe" a community. I'm hesitant to block a whole domain or user, but I would probably have downweighted a few by factor 4 if I could.

I like how Kagi (the search engine) does it: you can set a domain to (block, lower, normal, raise, pin) from the search results page. It's one of their most loved features. (Probably the five levels are a better UX choice than a slider or a number entry. My guess is that they search the first 100 results or so normally, and then reorder/filter according to preferences.)