I find the idea that commenters with higher karma having more powerful down-votes slightly disconcerting. My fear is that if people down-vote comments that are well meaning and relevant but they disagree content we will only ever see one train of thought rise to the top of comment threads.
This could start a vicious cycle where voting cabals of power-users form. For example if Idea X becomes popular among some members of HN they will be able to always steer the discussion to talk about Idea X or down-vote a competing valid Idea Y into oblivion. Comment readers could be converted to Idea X, as it is always appearing at the top of relevant comment threads. So now the voting cabal as even more members. Growing the dislike of Idea Y. The cycle then repeats. The discussion is then steered over time by the thoughts of a select few power-users.
Maybe this is just the natural order of things and I'm subconsciously afraid of change. Thoughts?