The question and suggestions are wrong, wrong, wrong and wrong. So entirely wrong!
There are three criterias for a question, which show up on hovering the up arrow:
- shows research effort
- is useful
- and clear
which means, you can have three brilliant answers, but there hasn't been any research effort which is a different thing.
Similar, a question might be not very useful. I would say that a very specialized question is less useful than a more general question. For example a question might be, whether names ending with ~stein like Rubinstein, Einstein, Wallenstein and so on origin from somewhere with the meaning of stone. Pretty general and maybe useful.
Only asking for Einstein is less useful, but at least it is a popular name. If somebody has an uncle called Waldstein and asks for that name, it is not very useful and would fit the somehow vanished bullet point "too specialized/localized" from the close-question dialog.
But there might be a specialist giving a good answer. If you want to vote on answers, vote on answers - it's simple as that. Play it straight forward and not around 3 corners.
People can search for questions by content and needn't search by upvotes. There are many good questions I'm not interested in. Vote them up like insane - I wouldn't read them (again).
The SE network does encourage such upvoting (my emphasis; uu) on questions ...
No, it encourages upvoted questions - the person responsible for such a question. Upvoting is encouraged too, but not as much as your list suggests.
Show some respect to the questioner
Show respect to the questioner in the chat. The voting is for voting on the question, not on the questioner. Don't abuse the voting system, especially not for welcome posts.
In 2 months no visitor will recognize that a somehow bad question was upvoted to make the questioner feel good, except you abuse the comment system too, which makes it worse. The system should be fair and clear and communicate what is explicitly stated (see above).
Highly voted good answers can only be written on a useful question
It is just wrong. Beside the arguments already made, the answer could be upvoted because it is making some popular claims, which wouldn't be what the system is intended to be, but why should such an abuse automatically jump over to the question?
Whenever we look forward to an answer of a question we can not answer easily the question may deserve an upvote ...
Yes, or it might not be a clear question and deserve a downvote.
Please do not downvote an otherwise well written questions when we can not answer it (this sadly happened in the past).
How do you know this? Can you read minds or did you downvote yourself?
What minimum requirements should a question have to be upvotable? How do we define a "useful" question? Should questions be edited if they have good answers but do not yet meet our criteria for being useful?
Requirements: See above: Clear, useful and shows some effort. If all points are met: upvote. If some are met, weight them.
A question is useful if the chances are good, that more people will have the same question, if it raises interest. If I'm interested in a topic, I tend to vote it up (but the other points, preparation and clearness can prevent it). If I'm not interested, I tend not to vote it up. This way many votes will show high interest and usefulness, low votes less so. If I'm not interested, but I'm impressed by effort and clearness, I vote up though to encourage the style of asking.
Questions should always be edited if you can improve them without changing the intent of the author, useful or not. I already edited some questions to improve the clearness or the spelling but voted to close because of other reasons.