Downvoting has attracted a lot of different opinions over the past few months. There are cases where people just downvote without giving any reason. It has become a fun activity for them. Without any reason, downvote cannot be justified. It's true that some answers deserve downvote but there are ones that don't.
To overcome this problem, I would like to propose a solution - whenever a user wants to downvote
they are greeted with a dialog box that asks for a reason as to why they want to downvote. Instead of making this optional, we can enforce this with no exceptions.
There are different views on this - some people say we should not force users to give reason for downvoting like this answer suggests but what I think is that giving no reason and still downvoting is not at all beneficial to community in any way. By giving a reason, that particular post can be improved.
Now there are generally multiple comments on a post so how to know which user downvoted and what is the reason for that? Well we could add a downvote icon to the comment that was given while downvoting. This way, users can know which is a normal comment and which is a downvoted one. It could look like this:
Notice the downvote icon on the left of the comment. This icon will only be present on comments that were posted while downvoting. We can add anonymity to the comment if we decide downvoter's name should not be disclosed but I think we should disclose it, this way we'll know which user is most active in trying to improve posts by giving justified reasons.
I think the time has come to look into this matter, your valuable suggestions are most welcome.