For context, the most recent version proposed in the other thread can be found in this post. It is very similar but has more detailed descriptions, and a mapping to the values of others scales (e.g. SAC, YDS) that should probably be considered tentative (as a 1:1 translation won’t be possible or desirable).
My own attempt at summarising the rationale can be found here.
I think your post is a good summary of the previous discussion, with some minor changes.
It would be good to hear from as many people as possible what they think about it. Especially mappers from around the world, where the terrain might look rather different from the Swiss Alps. We could also make some posts in regional communities. I am also thinking that a gallery of examples from around the world could be helpful, a bit like this one for smoothness. Between us we can probably cover a lot of different terrain types.