This was an idea that was flawed even before development. And all the clever stuff a writer tries to do after adopting a tough seed idea often falls short because all your energy and time is invested on remedying a basic defect. So naturally there is no question of trying to take it into a new level.
Now what is the basic defect? When you decide to make a film based on a woman who murders her seven husbands, you cant run away from the repetitiveness it will bring about while narrating the story. The audience knows what will happen, it is only a question of how it will happen. The writer rakes his brain trying to make every husband and every murder different. He tries to deal with the repetitiveness even with a forced in non linear structure (which has become a cliché in itself now). The ending of the movie was interesting, but it was too little, too late.
Still it is nice to see such a different (commercially risky) idea being made into a film in mainstream Bollywood. That itself absolves Vishal Bharadwaj of all his sins. This Khoon is maaf.