7. Before Watchmen
I know it seems unfair to choose this when the first Watchmen film wasn't a raging success, but it's the principle that applies to most prequels, be they comics or films; the seeming pervasive superfluity of the material. While I enjoyed Prometheus (pitchforks away everyone), I believed that it would have succeeded more if it had completely divorced itself from the expectations attached to a Ridley Scott-helmed Alien prequel. It would of stood far taller on it's own. The case with Before Watchmen is similar. The need for prequels was not present, and after reading most of the series in most or all of their duration, I can say that the problem with most of them was that they were stories that did not need telling. Except Minutemen. The only exception to the previous rule, Minutemen would make for a daring and edgy film, given that it was treated properly. However, every other series has proven to be an unnecessary waste of some shining talent, and that is a waste I can foresee should a Watchmen prequel emerge; many big names, much attention, ultimately for a final product that would almost certainly prove to be disappointing.