No, people should not have to mess with themes for this workaround. Just check (or uncheck) a checkbox.
Plug-ins can add partial includes to
"title": "My plug-in",
"description": "1-2 sentences about what this plug-in offers.",
All the first-party themes support this. Sure, third-party theme developers can omit support as of now. But I think that might change in the future. That is to say, to be allowed in the official plug-in directory, themes must implement support for Micro.blog features like partial includes. (Correct me if I’m wrong here, @manton.)
So, I would say this is an excellent workaround. It will work for everyone using first-party themes and, I would guess, most people using third-party themes.