Pollux In your video you wouldn't need to provide classes for everything, instead your approach could be used by others to build upon your work.
Regarding this part I'm not sure it's easy to build upon to add new classes. Pushing new classes to an element or body is very easy. It's writing the logic for each kind of class that's difficult. So even after watching my video, you would still be left with the most difficult part if you wanted to implement a new class for a new kind of thing 😬
From the educational point of view, watching this extension being written would primarily teach the various properties of objects like tags and discussions I think. Which is also an interesting thing.
I'll see what ideas I keep.
I need to build a public review+comment (google like) extension for one of my projects, this will probably be this week's extension. I will incorporate some extensibility aspects into it (server side though).