Problem: Allow displaying automatic stuff on content pages via MediaWiki messages (notices, user warnings, auto categorization, ...)
Proposed solution: Talk pages have specific MediaWiki messages (MediaWiki:Editnotice-NS_number-article_name and MediaWiki:Editnotice-NS_number) that can be modified to show specific content on each talk page. I propose adding a similar option to content namespaces.
Who would benefit: all editors
More comments: It could be used to show instructions for new Draft pages automatically, to categorize all kinds of content automatically (drafts, documentation subpages, articles whose name begins a certain way), to show protection templates automatically, show messages at the top of user pages, etc.