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.
Yes.. You have very good idea.. Hope developer team could implement this..
I would prefer(at least for a quicker solution) the need to make a minimal 127 character reply to the downvoted post so in order to be able to downvote. It doesn't need to completely remove the "separate mana" for downvote, but it would obligate the downvoter to make a statement before casting the downvote, even it is pasted auto-text or completely gibberish of random characters.
That way the community could at least have access to the downvoter's reasons to do so and, if it's the case, counter it with their own upvotes.
I would prefer that also, that in order to down vote you must state a reason. For some reason though people do not want to have a mandatory comment of any kind. They always point out a comment is not need to up vote so why one to down vote. They do not see the difference in an up vote being a positive action, and a down vote as being a negative action. No society I know of has ever required justification for an individuals positive actions, only their negative actions. The people that do not want a comment or the ability to give the down voter themselves a down vote are the one that think down votes are a positive action. They are not the are a negative action and a control action.