To assign category ID 9 to post ID 1, I currently need to:

POST /wp/v2/posts/1/categories/9

This seems a bit wonky. It's also not possible to control the order of the terms, or assign more than one term at a time. See #1421

I'm not sure why we created separate endpoints for term management in the first place (I didn't search past discussion). What if, instead, we dropped the Post Terms controller, and magically registered categories, tags and other custom taxonomy-based attributes as an array of ids to the Post schema? This would be more in line with author, featured_image (which are ids that represent other resources).

cc @joehoyle

From #2016 (comment)