I think the URL design of stackoverflow leavs room for improvement. The id should not be necessary. StackOverflow demands unique questions. If a question doesn'

I think the URL design of stackoverflow leavs room for improvement. The id should not be necessary. StackOverflow demands unique questions. If a question doesn't have a unique slug, is the question unique? Great URL design to me is if the slug is suffficient for uniqueness, without an id.