Let's collect some more feedback.
I see that we are currently talking about separation (during localization process) of name and file name properties that can be treated as metadata and everything else (that is related to content part) like page template, list of components, and metadata fields assigned to the page since they are part of page schema that defines page layout (regions).
So I would separate ideas about partial localization and the possibility to push/pull content changes from parent items.
Please share your thoughts on what is more relevant for you.
Either page file name changes are often required for localized content or the possibility to synchronize content with parent item would be more beneficial
For name and file name we might change these properties to allow editing them on shared items. So you do not need to even localize