The number of plugins are indeed growing. A scan though the Plugin & Content Manager brings ups some related plugins:
Save / Restore Layout
This plugin implements footprint modules or snippets feature. The plugin saves partial layout corresponding to footprints from one hirearchical sheet so that it can be restored in other projects. All projects have to use the same hierarchical sheet schematics. If the schematics has been edited, the plugin will refuse to restore the layout. So in projects where you need to change the schematics slightly, first restore the layout and then change the schematics.
Schematic Blocks Plug-In
A plug-in can be used to save circuits as blocks. Then these circuit blocks can be reused in different projects. This plug-in aims to reduce schematic drawing time significantly.
To create a schematic block, first, select the circuit and copy it to the clipboard (Ctrl+C). Then open up the plug-in and give it a name by writing it in the text field at the top. Click the “Save Block” Button to save it in the working directory. If you want to change the working directory, you can click the “Change Working Directory” button. All the blocks are saved in the working directory. Also, all the blocks in that directory will be listed in the List box.
HierarchicalPCB
Define a sub-PCB next to your sub-schematic file, and HierarchicalPCB will propagate that layout to the final PCB. Organize your PCB layouts for maximum reusability!
I guess that starting with a plugin is not such a bad Idea. Partially it is also an experimentation area to try out new Ideas, and to see how useful such Idea’s are. When applicable, parts of a plugin (or the Idea of the plugin) could be (re-) implemented as a native KiCad part in a later stage.