Desired outcome:

Similarly to the Page History where we can compare the current page with a previous page version, it would be great if the capability of comparing a current version of a published page with the current version of the template that the page originated from was introduced.

Furthermore, when detecting changes that were already done to the original template published version, provide the ability to "merge" those changes in a way that the current page version is once again "up-to-date" with the original template that the page originated from.