Thanks for the thoughs
Here’s my opinion:
(1) I would **not **go the “open cycle map way” because then we cannot differentiate a foot path from bicycle path. if a foot path is non ridable the tag mtb:scale = 6 (giving it a black & orange color) will show this. If a foot path is ridable, mtb:scale = 1 to 5 will show the difficulty (see foot trails tagged in Yagur area)
(2) The “samash” sometimes interferes’ especially if it is wide (like Shvil Israel) - needs some thought on how to make it better.
(3) Good idea to show bike shops
(4) Good idea to show tagged trails in bright yellow in lower zooms
(5) Good idea to show direction
(6) I would stay with the Norwegian concept, what does need thinking is the “samash”
Regarding the 1st point.
OCM marks bicycle=designated and bicycle=yes in blue and bicycle=? in brown. Standard mapnik marks bicycle=designated in blue and bicycle=yes and bicycle=? in grey. So OCM is more liberal, as should be the case for a bicycle-oriented map.
It will take time till we tag all paths with the correct MTB:scale, and until than we want to know what is rideable and what is not.
The bright yellow annotation is based on the class:bicycle:mtb tag.
Currently, there is only one trail with a class:bicycle:mtb and it is rendered correctly as transparent given its class:bicycle:mtb=-1 tag.
See the overpass-turbo map of class:bicycle:mtb trails
Just a note on the bicycle=yes tag. This is, as I understand it, a legal tag. Meaning if you are allowed to ride there or not. Same with bicycle=no.
Here in Norway many paths have been tagged with bicycle=no because some people have thought it wouldn’t be possible to ride a bike even if it’s allowed. Not thinking of how skilled many MTB riders are 
Seems that the same has happened here as well
Some highways are rightfully tagged as bicycle=no, but some trails are wrongfully taged the same…
As the word is spread now, it will probably be corrected