As for the Topic of the Day...
Well, I actually liked the John Doyle Sweeney Todd and Company for that matter. Do I want to see that approached adapted for every single show? No. But I have to give him and his team of actor/musicians for committing to the concept - and for memorizing all those notes!
As for things that have not worked, well, the two that come to mind are productions of Shakespeare's Macbeth and King Lear. In both cases, some gender-switching was involved. In Macbeth, Banquo was played by a woman which really played with the whole dynamic right at the top of the play. -And it was never made clear whether if Banquo was supposed to be a woman, or "simply" a woman playing a man. The King Lear was basically Queen Lear. The performances were fine, but, again, having a very Male part portrayed by a woman just did not really serve the play all that well.