The issue of having the option of giving someone else one or more of your own points has come up before not too long ago. I'm on Scribophile as well where you can do this. Someone reviewed a piece of mine and blew it wide open for me. Like I hadn't understood what I was really writing about until I got their feedback. To show appreciation, I gave them one of my points (as well as reviewed something of theirs). Simple as that. The computer programming necessary may not be as simple.
As far as a reviewer ranking: What are we going to rank? How many reviews someone has done? What if a reviewer does the minimum and other people spend a lot more time going above and beyond? What if one person's feedback, no matter how many observations they make, is more valuable than someone else's to any given writer? How will we measure that? Who cares? If you don't review, you can't post. Clear as day. I'm here to improve my writing skills. But if some of you want the competition, I have no objections personally, I'll simply ignore the whole thing.
As far as accruing points: I have .77 at the moment. I'm relatively new here. Joined Feb 2017.
I've done a total of 77 (3 are drafts still) reviews and received 82. I'm aware of owing 4 at the moment (which is why I got on the site just now and what I should be doing).
I post my work. Sometimes I delete something I've worked on for awhile and repost it so that people who read it before can read it again, giving me the benefit of their familiarity with the piece.
Generally, I spend at least an hour per review. I'm always surprised how the time has flown by, except for the ache in my shoulders. Sometimes I just stop because I have my own work to do, though I learn A LOT from doing reviews.
As far as reviewing goes: I would like to see how others develop their pieces following my review, and the reviews of others. I'd like to see the development.
Ideally, I'd like to be on a path with a small group of writers -- some simpatico souls -- and actually follow each other to the completion of our respective pieces. Contact me via personal messaging if you're interested in this. Please look at my work and make sure it appeals to you before you do this.