The below constitutes an attempt to provide a comment template to accompany down-/close votes. A copy has been placed on the list.
This question is of insufficient quality (Version 6 -- reflect the new "on hold" status)
If necessary, this can be preceded by Hello, welcome to Math.SE.
Your question is phrased as an isolated problem, without any further information or context. This does not match many users' quality standards, so it may attract downvotes, or be put on hold. To prevent that, please  the question. This will help you recognise and resolve the issues. Concretely: please provide context, and include your work and thoughts on the problem. These changes can help in formulating more appropriate answers.
Your question is phrased as an isolated problem, without any further information or context. This does not match [many users' quality standards](http://goo.gl/mLWc8), so it may attract downvotes, or be put on hold. To prevent that, please  the question. [This](http://goo.gl/xQWVb) will help you recognise and resolve the issues. Concretely: please provide context, and include your work and thoughts on the problem. These changes can help in formulating more appropriate answers.
(Note: The link under "This" (which has been shortened to allow for more text) in the comment template should be updated to point to a to-be-created "Proper question formatting" thread in place of the current one, which only deals with homework questions.)
One thing that I would like to see added to this is a word on what to do once the question has been edited -- so as to make it more probable that indeed the negative votes are removed. Suggestions directed at this are appreciated.
In some sense, I think close votes would be more appropriate for this type of question than downvotes, because they are easier to cancel by arbitrary users (using reopen votes and -requests if necessary). This as opposed to downvotes which are more visibile, and can only be cancelled by the person that cast them.
One thing that certainly would help increase the effectiveness of suggested template is a possibility to revoke close votes; see this thread and links there for more information.
Following Jyrki Lahtonen's answer, I think it is good to include a word on the intended use of this template. It is not intended to be cast in stone, nor is its use. Please, always use common sense and your truthful judgement before adding it anywhere. This will help to prevent unnecessary frustration for questioners and the share of people opposing the measures that this template suggests.
Addendum: After having noticed that the comment character limit prohibits people from including the necessary nuance in their statements, I have created a QA Policy Discussion chatroom to circumvent this. All are welcome to share their thoughts to come to a consensus; the only requirements are that one is thoughtful, willing to listen to others, and most importantly, polite.