First, I'm not sure if I agree with the ban, but I would allow EN to post one last apologia at least.

Second, considering karma as a property of users rather than of comments is toxic. Let's stop it. Let's consider the sum of all comments and post that happen to be written by the same person no more meaningful than the sum of all comments and post that happen to be posted the same day.

If we must rank users, e.g. to decide whom to allow to post articles, let's have a system where users can rate each other directly (but anonymously). Maybe make higher-ranked users' ratings count more (i.e. each user's score is proportional to the component of the eigenvector of the matrix of ratings with the largest eigenvalue).