8) Superman: Flyby
As well as reinvigorating the Star Trek and Star Wars franchises, J.J. Abrams nearly did the same for Superman with Superman: Flyby.
What probably stopped this one being made was its sheer off-the-wall quality, as it would have taken a lot of liberties with the source material. These include Krypton not being destroyed, Lex Luthor being outed as a Kryptonian and a lot of Matrix-esque super-powered Kung Fu.
Brett Ratner was set to direct Abrams’ script and was looking to cast an unknown in the role. Supes himself, Christopher Reeves, attached to the project as a consultant, lobbied for Smallville’s Tom Welling to get the part. Meanwhile both Robert Downey Jr. and Johnny Depp were considered for Lex Luthor.
Despite all of this, Flyby never actually got off the ground. Abrams and Ratner were replaced by Bryan Singer and the film became Superman Returns, which went the other way and became overly-faithful to the original Superman movies.