Community documentation (not technical documentation) is being migrated from at least one of the wikis to Discourse, and those wiki pages removed.
My opinion #1 is that it’s okay to delete some ancient information that is outside the current support window. The wiki.ubuntu.com (which more folks can edit) database retains the older versions of each page. So severe edits can be undone if needed – as can mistakes. People make mistakes!
My opinion #2 is that it’s okay (and welcome) to A) put in the effort to rearrange and update sections to wiki.ubuntu.com – and sub-pages are a good idea for that. It’s not okay to B) broadly implement a new structure single-handedly, creating possibly hundreds of new pages, in the hope that “somebody else” will come along to fill the empty pages and fix all the broken links.
(I think that that A is your goal, and it’s great!)
My opinion #3 is that there are likely some folks willing to join and help if you let the wider world know that you want to reboot the Documentation Team: Ubuntu Weekly News, Ubuntu.Social, OMG, regular updates, etc.