There is already a feature to delete CMS items through the API, but it's downright broken as it is today.
If there are any links to other CMS items at all, you simply cannot delete the item and it returns a "still in use" error. For someone with thousands of blog posts that are cross referenced with eachother through tags and links, going into them manually and removing every single link just isn't feasible. Even with just ten or a hundred that would take a long, long time - and the point of the API is to automate stuff like this.
Please add support for auto-unlinking and/or just straight up deleting the CMS item without requiring manual unlinking.