Hmm~ Wouldn’t that mean needing the API of every single WK user? 
If it’s even possible, I think it would be better for it to be an opt-in system only. As much as rankings encourage some people, they discourage just about as many. So having everyone being able to see anyone’s accuracy, and people feeling like they’re being compared to everyone else would certainly be a negative for a large number of people.
The closest thing that I’m aware of is a script where you manually add members, so you can keep track of their level-ups and have a sort of leaderboard that way. I know some people use it for friendly competition of over-taking or keeping up with each other through level-ups. ^^