Since Blender 2.8 also is about cleaning up some confusing parts of Blender…
Wouldn’t it be a good time to remove the old smooth/flat faces feature? It doesn’t even produce correct shading. Just create a smooth cube and set the top face to hard. The remaining smooth faces still behave as if the top face also is smooth.
And with the auto smooth feature it actually isn’t needed anymore. Since this also takes sharp edges into account it can achieve the same (and more) in a correct way.
What do you think?