Downvoting on "Question" - GUI proposal
I think that down-votes are more important as they can give the users asking the question the opportunity to work on their question to make it more suitable for an answer. It could also indicate that this is not the right place to ask this type of question.
I can imagine that down vote list could be dynamic, site specific or even generated based on tags used in the question. This proposal not meant to define a one and only possible solution. It is only a presentation of a concept.
Stack moderators could contribute in accepting or modifying list of available down-vote buttons. Users could collaborate and make a proposal to add or change available options.
Consider the following GUI modification:
This approach gives the person asking the question much better feedback on how he/she can improve the question or if he/she should continue to try to find the answer on this particular site.
This solution would also give better guidelines on when the down-vote should be used and when a short comment describing the issue with the question would be more appropriate. At the same time this do not force anyone to comment when down voting a question. Down vote would become self descriptive so in many cases the comment would not be necessary. In most cases users not to care to live a comment anyway when down-voting. This approach could solve this issue.
Constructive and clear criticism should be always welcome. Informative criticism will allow improvement.