In order to ease updating imported or appended objects i suggest to make a function to redo that on click.
The objects that are appended or imported could have a hidden property whether they are imported/appended or not and the source location. The button could be placed in the context rightclick menu in the outliner. The function should change the object entirely for the first iteration of development. The further improvement could be updating some specific datablocks, such as mesh, material, modifiers, etc. Blender should ask us how we want to update current item after selecting the "re-import/re-append object" item in the context menu.