In the ongoing discussion, I have noticed that it isn’t an easy task to integrate big country forums, like those of France, because Discourse currently supports only two category levels.
I would suggest to introduce namespaces for sub-category names, as they are used in programming languages (e.g. Java).
The idea is, to use main-categories only as container for sub-categories. And the sub-categories contain country main-forums as well as sub-forums at the same category level (2). The virtual hierarchical structure is a result of the namespace conventions, if the sub-categories are sorted by name.
In the following visualisation, I use the Windows File Explorer - folders represent (sub)categories (except “Discourse”) and files topics.
Another point in this context is the layout of the platform’s main-page.
Due to the large number of countries and their sub-forums, it’s problematic to show all the sub-categories on the platforms main-page, because the place there is limited - and I thing, this will probably increase in future.
So, I suggest that the main-page of the platform does not show sub-categories. This makes the surface clean and clearly arranged and the users should be able to easily find the right place for their needs.
For advanced users, it could also be very useful to see shortcuts of their “Watched” and “Tracked” categories at the top of the main-page, to quickly access them.
Surely, the biggest disadvantage of this concept is the long sub-category name, but perhaps this can be a starting point for further discussions.
ps: Above I used “platform” instead of “site”, because I think this project is much more than a (web)site…