After a successful Man of Steel film in 2013, I would convince the sudio to green light a Flash film and a Batman film in the same universe (highest selling heroes other than Green Lantern). Because of the nature of the industry, the movies would take about 2 years to reach theaters. That puts us at 2015. During 2014, studios would green light a Wonder Woman film and a soft reboot of Green Lantern (like what the Incredible Hulk did--no more GL origin movies). These two films would come out in 2016. The Wonder Woman film would introduce Steve Trevor and A.R.G.U.S.
The JLA film would start production in 2015 after the Batman reboot, and it would be released in 2017. Part of the film would deal with the origin of Cyborg--bringing our membership up to 6.
After the JLA film, Aquaman, Hawkman, Zatanna, Captain Marvel, Martian Manhunter, Cyborg, and others could be put into production along with the sequels to Superman, Batman, Green Lantern, Wonder Woman, and Flash.
How Would You Make A JLA Film Come To Fruition in 5 years?