I really like the idea of introducing some form of randomness to prevent gaming, social stratification, and other unintended consequences. My immediate thought

I really like the idea of introducing some form of randomness to prevent gaming, social stratification, and other unintended consequences. My immediate thought is to suggest some type of majority voting and maybe even random bagging -- e.g., show the "endorse" link to a few random users (or groups of users) and endorse any comment that gets majority vote.