Internet searches tell me that Gwenview if kipi-plugins are installed. I have no metadata editor in Gwenview (16.08.3), but do have kipi-plugins (5.3.0) installed. My impression is that I may not have this specific plugin installed, or that is has been removed from the plugins, or...

Can anyone tell me whether or not I can have a metadata editor in Gwenview and if so, how?

i found the same problem -
this answer shows a screenshot with the metadata editor:
https://superuser.com/a/702417/95719

i also installed the kipi-plugins
Version: 4:5.6.0-0ubuntu10
and there showed some plugins up in the plugins menu.
but no 'Edit all metadata' option..

is this editor removed?

sunny greetings
stefan

ok some more detective work later i found
Bug 371820 - Kipi plugins are working but with less features than gwenview was kde4 app
https://bugs.kde.org/show_bug.cgi?id=371820

so it seems it is just not ported..

i have created a wishlist item:
https://bugs.kde.org/show_bug.cgi?id=399069

sunny greetings
stefan