There are a few distinct use cases for RSS readers with
very different requirements for automatic filtering.
I use RSS readers to keep up with infrequently-updated fiction and webcomics. In this use case, "suggestions" are worse than useless - if I miss a daily or weekly strip or, worse yet, a chapter being posted, that can cripple my enjoyment of the story. I check my RSS feeds once ever two or three days and read exactly every single post in them, all twenty or forty of them.
There are other people (myself about six years ago, for example) that use their RSS reader as a news firehose. They get a hundred posts an hour and even checking their titles manually would be difficult. In this case suggestions are not just a good idea but actually required.
Personally, I'd like an RSS reader that has a per-feed toggle for automatic filtering. I so far haven't seen that.