Experimenting with a different formula, slightly different ordering but should give preference to those who are more in need of ratings, and prevent super-raters from getting too much karma (diminishing returns).
Formula is:
karma = ln(1 + ratings_given) - log5(1 + ratings_received)
If you have ideas for other formulas tell me and I'll try them out.
Edit: I also personally think that a karma system like this is flawed. I wrote about why, and my proposed solution here: https://itch.io/t/527869/karma-system-for-the-game-jams#post-895699
I added the karma sorting option as an experiment, something to try out and see how it works.