Completely disable rewrite rules(feature request)

Hello, I was using an old plugin to do my needs with disabling feeds. It has an awesome feature that completely disables rewrite rules for all the feeds. It just gives error 404 right away. See, my website has a lots of content. While using disable feeds wp works, it takes some time like 10 seconds for it to return error 404 for my feeds. It clearly uses resources on my website. But it you add a feature like what I said, it will instantly throw a 404 error