410 for deleted content?

From SEO point of view, if address is already indexed by google etc. it is better to create 301 redirect for delated page. If there is no new – replace page – than redirect it to homepage.

I changed the permalink structure of a WordPress website months ago from example.com/category/post-title to example.com/post-title. I have a 301 redirection active (/category/* -> /*), I disallowed the “folders” via robots.txt and Google still shows the “old” links, so I’ve got duplicate content since then.

I’d really like to have an option for 410s in the plugin, too – that would be much simpler than hacking around in the .htaccess file. ??