As this is the current, active, RFC, I’ll write down my view, mentioned in other threads.
Scale
You are trying to come up with a difficulty scale, from what I understand. This is exactly what the SAC scale does, too. And a few others, as well. So, any argument that goes against the SAC scale applies to the new scale, too. Just look at the history (of the SAC or UIAA scales) and you will see that nothing new is being done here. Same old problems, same old solutions.
Literally every negative argument from the first post will apply to the new scale sooner or later.
Someone who doesn’t bother to check the values in the SAC scale will also not bother to check any other scale.
Scrambling
I see a problem with classifying scrambling. It already belongs to the hiking scale (SAC T4-T6) and the climbing scale (UIAA I-III). Even SAC and UIAA overlap. But, the more the merrier, having another scale may make someone happy, so why not?
Equipment
The use of equipment can hardly be mandated. Just look at the Oscar-winning Alex Honnold and see what equipment he uses for routes we can only dream of.
Via Ferattas have a relatively standardised set of equipment. There is also a set of safe equipment and standards for climbing, as recommended by the country alpine/mountaineering clubs. But nobody is going to fine you for not wearing a helmet.
Tags
Finally, it is worth linking this to the efforts in defining new tags for pathless and perhaps adding climbing to the same level, so I’ll add links here: