Given that most of the answers are getting downvoted like crazy, I'll throw in an extra one :)
The root problem here is bad questions, but unfortunately all the ideas we ever have either get shot down, or have already been implemented and aren't sufficient.
So we come to limiting new user accounts. My understanding of the question was that it was about people abusing accounts to get around bans. Answers seem to have wandered into limiting all new accounts, which could explain the downvotes.
So what we really want is a way of increasing friction for someone who is asking bad quality questions: the problem being that there is no easy way to differentiate an 'innocent' new user from a 'banned just now' new user.
I know hell bans have been suggested and downvoted before, but I wonder if some kind of 'time limited' hell ban might work? For example, following a mod banning a user for bad quality questions, their questions would sit in some kind of purgatory, then after a week they'd be notified.
Not perfect, but it could just add a bit more friction. To obfuscate further, the question could (for example) still be visible via direct url, or by looking up the user, but not figure in any default tabs?
