Down voting system does need to change. It is already a two step process to down vote, adding in a set of check boxes next to the reasons to down vote would be a simple solution, and then an auto comment added that @me down voted @you because of 'the reason for down vote selection'. What this would do is truly allow the community to decide if the down vote was justified. The other benefit is there would be no more blind down votes, no inability to down vote a serial down voter back. A comment was auto left by them that can then be down voted back.

The other thing I would like to see to fix the down vote is that when the down vote is for reward disagreement then the full force of the down vote go against the highest post rewarder and not against the post creator, the post creator has no control over who votes for nor how much they vote for their post, so their reputation should not be harmed. If three people or more down vote the post for excessive rewards then the top reward issuer should receive no curation at all from that post payout.