See proposal at Commons: Categories have evolved to be the main tool for organizing content at Commons. However, they are by default placed at the very bottom of the file description page, where hardly anyone who's not looking for them will ever find them. There already is a gadget called Place categories above content, but below image on file description pages and consensus to enable it seems pretty clear to me. Could possibly resticted to content namespaces (files, categories, galleries; possibly graphs in the future)
It was pointed out that just enabling the js gadget per default would be a bad idea for technical (?) reasons: "This needs a integration in MediaWiki to avoid Jumping Content."