I do hope, you are reading this wrong 
I at least have no interest in creating the one and only scale that encompasses any imaginable scale on earth as a subclass behind five colons. I alse have not the least interest in replacing sac_scale. Going this way, any proposal is doomed to fail.
sac_scale has its uses in niches. But it will never be a key that meets the needs of a wider class of map data users. Something that openstreetmap needs, and sac_scale needs that too, so it does not get misapplied due to factors already mentioned.
One of the naysayers argument in the scramble vote was, if the national map has a path there, openstreetmap must have a path there too. Here two videos of where our national map has a path.
First one https://www.youtube.com/watch?v=X0O0lWsajN0 starting the trip from Hungerburg 
UIAA II foto at 6:45 and a bit of UIAA I at 6:30. Not much impressive, but this is canonical grading.
Second one uncut https://www.youtube.com/watch?v=v0QqhTJI5OA : As smart people do, up the eastern ridge in order to end the trip with a scree run, video linked some post above. At 29:00 on the summit. Then down the western arete with the short UIAA II sections in between mostly UIAA I and some walking terrain where even a path emerges at times.
UIAA II section not much exposed, so not really challenging. Route in few places exposed a bit. We here say, Es pfeift - It gets airy. But not too much and not in the difficult places. Tagged sac_scale T5 (E) and T6 (W) in OSM. On site, the Western side is called an “Alpine Route” - decidedly telling guidepost readers that there is not path there.
foot_scale=no, in my opinion. highway=scramble in my opinion.