Anything that stops your question from being visible for a reasonable amount of time, such as vetting the question could end up frustrating the user with genuine intentions.
Ultimately, most people come to sites like this when researching questions they have. If they find an answer, they don't need to become a user and in most cases go on their merry way. It's probably more likely that genuine users come here to ask a question they can't find an answer for after a little bit of searching.
These types of users wouldn't mind answering a few more questions that act as an educational tool for both them as new users as well as to SO as a source of user info.
What I would suggest is that after constructing your question, when you click to submit it the user gets asked some questions to ensure they have followed basic question protocol, such as 'Have you searched SO for similar questions to yours?'. This would show perhaps the top 5 questions brought back according to the title. Other questions could be 'Does your title accurately summarise your problem?' and show a couple of examples of good and bad. Basically, add in a question for each of the key points in 'How to ask a good question?'. These would be simple 'Yes / No' answers (on ticking 'No' you go back to editing the question). It may also be a suitable place to gain further useful information about the user, but that would be for another discussion.
The aim of this process would have the following benefits:
- Educate the user in how to ask a good question.
- Not too much of a hurdle for the genuine user. After all, if you've gone to the trouble of writing your question you don't mind answering a few more quality control questions to get it on the site.
- Add more steps to the process to slow down malicious users.
After a certain threshold of questions asked combined with question score these quality control questions could be removed. This approach would have the benefit of being a 'softer' approach compared to perhaps applying a technical rule based strategy that may unfairly disadvantage some genuine users (phone verification etc).