When I export a notebook with sub-notebooks as HTML, it will currently have an index HTML file that has all of the notes from all of the notebooks in a flat structure. I think it would make more sense to be able to navigate this like a wiki where the index file has links to other index files for each of the sub-notebooks. Then, each of the sub-notebooks will have their notes.
Another option which might be easier would be to still have a single index file but then indent notes under the name of the sub-notebook that they are in.
When I export a notebook with sub-notebooks as HTML, it will currently have an index HTML file that has all of the notes from all of the notebooks in a flat structure. I think it would make more sense to be able to navigate this like a wiki where the index file has links to other index files for each of the sub-notebooks. Then, each of the sub-notebooks will have their notes.
Another option which might be easier would be to still have a single index file but then indent notes under the name of the sub-notebook that they are in.