Here's another idea. Issue daily Steem-UA tokens based on the rank or whatever criteria. Maybe token issue would be based on rank alone, regardless of post frequency. Or maybe it's a combination of rank and post. Whatever, doesn't matter.
Then, anyone can look at the sum issued over time to the account to determine rank.
I do something similar here, in my STINGY token report:
https://steemit.com/steem-engine/@inertia/stingy-news-the-stingy-oracle-is-still-stingy
That report doesn't simply look at the rich list. This is the simple rich list, see the difference?
https://bloks.xyz/token/STINGY
My report shows how many people earned STINGY. The rich list shows how many people have earned + bought (market trades), so the rich list might be less interesting.
I could see a Steem-UA implementation leverage this same dynamic.
Maybe you always issue 1000 tokens every day, but it's divided by the top accounts according to the current Steem-UA rank.