So who's fault is it if it fails?

Heavy emphasis on "if" as I think this looks really good. There's a lot going on in the trailer but if it is more than 3hrs long, then maybe they can pull it off and the plot will be consistent and easy to follow. Whether you actually like the plot or not is obviously a whole different story all together, but if it does fail, (bad reviews), who's fault is it, Snyder's or Joss Whedon? I can see it now with some DC fans on here; if it's a success (which I hope it is), it's because of Snyder; if it's fails, it's Whedon's fault.