By default, when a page is created by using a page template, the propagation of changes from a site template is enabled. While this is desired in some cases, in some other it is not and it forces the site admin to disable it by going to Manage > Page for every page created.
To avoid this the following options should be added:
1) When adding a page from the pages management UI, if a page template is chosen, a checkbox should be shown to enable or disable propagation of changes
2) A portal property should be provided to allow setting the default value of the property. This property will be specially useful for sites which create most of their pages through the shortcut in the dock bar Add > Page which shows a very simple UI and thus a checkbox does not currently fit.