We all have heard the giant tease that a Justice League movie is in the works. Some here believe it doesn't need solo movies to be sucessful others think the opposite. Me I'm in between. I would like to see Warner Bros do something similar to Marvel Studios. Something like this.
Man of Steel:Establish Superman, and hint at Gotham City. Maybe show it on the news, and have Clark question wether he should move there. Then later in the movie have him see the news again and see there's already someone protecting Gotham.
World's Finest: For some this may seem outta nowhere, but to do another Batman movie just seems superfulous at this time. So I'd say just bring him in like Marvel did with the Hulk. We already know him lets explore different territory. In this movie Superman and Batman could face a threat that is Wonder Woman related. Maybe someone like Ares is indirectly causing havok. But bring in a familiar villain or at the most a villain with connections(who isn't Lexi Luthor).
Wonder Woman:Explore her origin, and have her creation be the result of the worlds finest movie. This is when Ares can get the spot light he needs. While during her origin Diana should come to know how Ares was stopped the first time. At least at the 3rd act of the movie. Which will lead to a Trinity movie.
Trinity: An intergalactic foe I would prefer Brainiac to come down to Earth. As in his character searches for the planets knowledge. But in the Trinity he sees something special.
Superman represents what mankind can become.
Batman represents what mankind truly is.
Wonder Woman represents the change that must take place for mankind to reach its potential. The middle ground. This to me would be a good reason why Brainiac would want to study the knowledge of the Trinity .
Green Lantern:While attempting to stop the Brainiac invasion Abin Sur dies. And his ring goes to the nearest planet to find the next recruit. The main villain of this movie I feel would be best is Atrocitous. It could show the connection between anger and will power. And see wether which is better for use. I find this idea cool since Hal got mad while fighting Paralax and gaining the will power to beat him in the original Green Lantern.
Flash:Sorry I don't know much about Flash. But he is still very essential to the original Justice League team. Mirror Master or Captain Cold maybe. But all of this would lead up to the grand finale.
Justice League: Where Warworld descends upon the Earth. Calling for its most powerful protectors to fight back. Mongul, Lobo(who is only there because he gets to kill for free and has gets whatever he wants.) Atrocitous I'd like to see come back. Using WarWorld as a means to use means to gain an answer from the universe. The question being about the inevitable Blackest Night prophecy.