The problem with exclusion filters is that they're filters. They work only to the extent that the map matches the territory - i.e., to the extent that people are properly tagging their content, such that the tags on an item reliably correspond to things about the content that people commonly want to find or exclude. And we don't have that here. Exclusion filters would be a huge improvement, but the tagging system has been so bad for so long that you would need a "hide this item" option anyway.