I like that I can drag content around in the outline. This process seems a bit more difficult in the document itself. In particular, it seems rather awkward if not entirely akin to "hit or miss" to find the right place to "grab" to move a paragraph, figure, or equation around in the document itself.
Could you improve on the size and denotation of the "drag + drop handle" for content in the document area. Perhaps this could be as simple as adding a noticeable vertical bar on the far left of the content item (and to the far left of the + o + tools) that can a user can grab.