I wouldn't mind a recommendation engine based on my RSS feeds. But when I subscribe to something via RSS I want to see all of that feed. I can manage unsubscribing myself.
This is exactly what I'd need. I don't really use RSS anymore, but when I did I had the problem that some sources (e.g. some random person's blog) would publish once every few weeks and I'd want to see every post, but others (e.g. the Guardian) would put out multiple posts an hour to the point that subscribing to them would drown out everything else in my feed.