+1
Would be a cool plugin! I do a lot of ‘professional’ writing, eg reports for senior execs, and in this case structure is almost more important than actual words. Mapping out the hierarchy of sections/sub-sections/arguments is something we do manually.
Also, not sure if anyone has ever done this, but it would be killer to give it outliner functionality – rearranging things in the mindmap will rearrange them in the .md text. Definitely not core Obsidian function, but perhaps a plugin could do this.