> a stream processing tool for end users
This is it! This is the fundamental problem that we need to solve, and what RSS is very poor at addressing today. I think that being able to process massive content streams in a human-friendly way is one of those problems that would be world-changing if solved effectively. Facebook and Twitter have failed at this so far, with far-reaching negative consequences for societies.
My gut feeling is that this probably means that we need a paradigm shift in how we relate to content streams. I think your move towards algorithmic transparency is a step in the right direction, though it may have to be bigger than that.
I think the fundamental design flaw of modern content aggregation sites such as YouTube, Facebook, and Twitter, is that lack of transparency. They think that they know what's best for you.
1. You don't know why you're being recommended what you're seeing.
2. You can't teach them to avoid topics. You can only mark individual videos/posts as "not interested" and hope The Algorithm takes the hint. Likewise, you can't teach them to recommend more of a certain topic.
3. You can't see a feed as someone else, so everyone is in their own bubble by default. Reddit and Hacker News avoids this issue by showing everyone the same feed.
4. They tend to have poorly thought-out metrics for relevancy. For example on Facebook comments, users tend to use the Laugh and Angry reacts as negative signal. These comments also get a large number of negative comments. Facebook is completely blind to this, and shows them at the top since it treats all interactions as effectively equal. Cool, they've just built a system that boosts toxicity.