I would add an extra menu/menu entry for plugins (workbenches and macros)
*Install plugin: requires an url to the git where the workbench rests - then in the background a git clone
for every installed plugin:
*activate/deactivate plugin - hide/unhide in the list of workbenches so everyone can customize his workbench list
*update plugin: git pull
*remove plugin: delete the Mod subdirectory
every workbench should exist as a git repository
every workbench should have a master branch and a readme file , which can be displayed in the help window
and there should be a page on the freecadweb.org website with short descriptions and links
to organize discussion there can be a section in the forum "plugins", where functionality and errors of plugins can be discussed separated from the core freeecad.
is a good example to start.
here you can seee the state of the plugins, the downloads and the development story.
you have always access to the current version and the plugin update is easy too.
I can create a prototype of such an interface (still in python - I have not the time to start c++ coding)
or is there aleady something available?