After reading the recent announcement in regards to Doujinshi and Novels, I realized that the current search/filtering system is a bigger cause of this issue. The most complaints I see about these 2 categories of content is that they are not something the person wants to view. A proper filter/search system fixes that.

My suggestions are as follows.

1. Rename Categories/Tags to simply Tags. This would also apply to the Category Recommendations on a title's page. This is a simple name change. (hopefully)

2. Create a new overall filter/search option (in addition to Genres) that is labeled Category. Within this new Category option you can have Manga, Manhua, Manhwa, Doujinshi, Novels, Web Novels, Webtoons, Artbooks, Hentai and any others you fill belong. (Hentai is iffy, since it can fall under a category and a genre)

3. In the Genre filter/options we would no longer need Doujinshi or Hentai. As they would have their own overall category. Adult would stay as there are Adult oriented series that are not Hentai.

This would allow users to filter out categories and genres that they have zero interest in, while also allowing things to continue as they are currently.