There are approximately 20 users in this community who have the ability to delete bad questions (questions with a net negative score.) I think (not certain) I might be the only one casting delete votes.
When a question has a net score of -8 from the OP or adequate edits from users, it's probably time to get it off the front page.
Bad questions have some educational value (they show visitors what not to ask), but to have the really bad ones sticking around on the front page, especially if they have a reopen vote (or 4) might be the opposite of the desired educational experience; it might encourage people to ask bad questions anyway.
Is it time to start casting delete votes?
Edited to add: I don't wait for the question to appear in the queue. If it's a terrible question, and it has a negative score, I VTD immediately on seeing it. The reason is a hope that it will be deleted before it gets reopened, which happens frequently. Some would call that a power play. I call it making the site more focused on better questions.