I disagree. While some editions would be easily implemented that way, to me the idea of editions, or at least these editions is that they are self-contained full wikis. They will contain plugins, maybe many of them, but they may also override core systems as needed, from fairly small things like animation speed to entire new layouts, entirely new UX.
For instance, TidBits ships with two widely used plugins, Autocomplete and Relink. What if the wiki you want to add TidBits too is incompatible with one of them? What if the stylesheet I write hides important information in your application?
To me, a plugin is something that does a specific job and does it across a great variety of use-cases. An edition is larger. It is not meant for importing anywhere. If it can be built out of plugins, great, but we shouldn’t try to restrict ourselves to that.