I remember reading Catch-22 when I was about 20. I think it was Colonel Cathcart who had a system were some people deserved more votes than other people. I remember myself thinking that sounded like a good idea. But no matter how I twisted this idea, I could not solve the problem “Who decides who gets more votes”.
I encountered another thinker (Ben Paine) who devised a system that earning the right to vote meant passing a simple civics exam. Not a bad idea, but it’s not hard to envision nefarious forces developing or hindering that exam to their own benefit.