If the Portal for ArcGIS home page is set to view only mode, disable the home page editor and show a message at the top of the home page editor that says the home page is in view only mode.
We recently had an issue where after upgrading ArcGIS Enterprise our home page was somehow set to viewOnly and it required looking through the config settings in /sharing/rest/portals/self to find that. It would have been much easier if the home page editor was disabled, and a message shown saying that the home page was in view only mode.
