This has been a discussion going on about Stack Exchange in general for a long time. There's a similar post here specifically about Stack Overflow and a post here made 7 years ago. I also read a pretty nasty albeit interesting attack piece which you can read here.
What if instead of down-voting the question, links or examples are provided to newbie, to show them how to ask a good question.
From what I've seen, the link to "How do I ask a good question?" is often provided to posts that aren't up-to-scratch. I personally disagree with the notion of not downvoting because it serves a purpose, the tool tip sums it up:
This question does not show any research effort; it is unclear or not useful
If any question, whether you've got 1 rep point or 100,000 rep points doesn't show research effort, is unclear or just plain useless it should be downvoted. To do otherwise on first posts would just set the wrong precedent in my view and couldn't be managed even if we did want to do that.
I also think that, the first question should be up-voted regardless of its quality to encourage the newbie to participate in the community.
I disagree with this, again it would set a bad precident and may very well encourage users to keep writing bad questions. Of course we want new users to participate, but allowing bad questions, even for first-posters will lower the quality of SFSE as a whole. Salesforce Stack Exchange as a resource is simply more important than any individual user.
If the question is really bad, we should spent more time on the question to educate and help the person to modify the question.
I think regardless of if it's bad, very bad or very very bad we should do this anyway. As you've mentioned, we want people to participate but the whole is greater than the sum of it's parts, 2+2=5, that type of thing. We can only get there by being disciplined and using Stack Exchange the way it's designed, that good questions and answers rise to the top and vice versa.
I would agree that we could, sometimes, type things in a nicer way. I include myself in that notion too! Ideally we'd live in a culture where, as Jeff Atwood says in The Ten Commandments of Egoless Programming...
be kind to the coder, not to the code
... We might be kind to the asker but not to the question.
When people are direct in asking things like "What have you tried so far?" to a question that doesn't specifiy that, I don't believe it's an attack on a user personally rather than a critique of the question itself.
I do want to emphasise what Adrian Larson said, compared to other Exchanges, SFSE is MUCH kinder and considerate. Indeed I've seen comments and answers to questions on other boards that are just plain rude and some Exchanges have a very elitist culture. That, in my opinion, does not exist here.