The proposal isn’t mine, I just read and shared it :-) The blog post has a paragraph or two about multpile subfolders, as I read it, the specification is not clear on whether thats supported? But actually: at first glance I think this would be better to have, because it would possibly make synchronizing to a new PC/Laptop even easier. However, this only works if any machine-specific settings (e.g. “offset /size of window”) are not stored in config, as that might break if you sync config between a multi-monitor setup and a single-monitor setup. This requires a lot of thought…
That feels way too nested to be useful IMHO. It’s great for packaging dev tools, but not really for handling config directories for user space apps. I just want ~/.config/KDE/<app>