It probably have sense to introduce combined "Duplicate and unpublish" action to allow quick copy of documents, and also introduce some kind of "template/draft" flag, so newly created copy not became published, even then it has proper start/end dates set for that.
Then we promote "template/draft" document to regular one (by removing this flag on save/update), it will be saved as new document, not inheriting original document created/last modified dates. I think this approach will play nice along with the DNN page templates.
It probably have sense to introduce combined "Duplicate and unpublish" action to allow quick copy of documents, and also introduce some kind of "template/draft" flag, so newly created copy not became published, even then it has proper start/end dates set for that.
Then we promote "template/draft" document to regular one (by removing this flag on save/update), it will be saved as new document, not inheriting original document created/last modified dates. I think this approach will play nice along with the DNN page templates.