Currently, the only way to add a Markdown-based article is to set the whole site to Markdown, create the article, and then switch back to WYSIWYG. This is not good as most people creating new articles can not change portal settings.
Consider adding a markdown option to the Add dialog.
Leave the Article in MD unless converted to WYSIWYG.
Once converted to WYSIWYG, it can NOT be converted back to MD.
The wisdom behind this is that many developers writing technical documents are familiar with and already writing in MD in Git Hub. Allowing the creation of a single document in MD format eases their transition to Document 360 while allowing others to work in WYSIWYG.