May be the post is more interesting for European members, but I updated my Grading Hiking Routes article with the more and more popular and adopted Swiss (SAC) Scale. Would like to hear your opinion if something like it can become a standard on SP.

I like the system. Adding it to the pull-down menus probably requires involvement of SP's owners, which doesn't happen very often.

Individual SP page creators could use it on our route pages and link to this page.

That's a good initiative but I doubt people will follow it spontaneously. There should be a drop-down list at the creation of the page to choose every criteria, otherwise people will ignore it (and still, all existing pages would need to be graded)
Besides this fact, I also doubt about all people from all countries and all levels evaluating things the same way. Too many already existing standards, too many different perceptions of the difficulty amongst people, etc etc...
Just organise a hike with some friends of you from all sides (not only mountain-oriented people), and ask them all at the end of the same hike "what did you find the most difficult ?". Everyday's people write SP pages, so you'll get the same result here...