I think DC should make a JLA full length CG animated movie. Not a straight to video, but a theater movie. They could style it how they want, on a scale of realistic to super cartoony. And cast whoever they want as the characters. They don't even have to look the part, or be the right age. You could cast Belluci to voice Wonder Woman, some people say she is too old for the part. You could cast an actor who is too young to voice Flash. etc. They could even use motion capture like Tin Tin. Tin Tin, Incredibles, are great examples of what the movie should be like.
And that could help launch spin offs too, show the desire for a Wonder Woman movie or tv show when the Wonder Woman merchandise keeps getting sold out. Or the Flash could get his own movie finally. (Live action for both I would imagine.)
They could also make the story as grand scale as they want. Maybe Mongol attacks Earth, using Starro he enslaves large numbers of the population, and the JLA must save the day.
You could be as elaborate as you want with the powers. Martian Manhunter could alter his shape in three different ways in 5 seconds while blasting lasers from his eyes and flying only to be stopped cold in a second by fire.
In cartoons people are more forgiving, more accepting of things looking silly. So their brightly colored costumes wouldn't look strange. Flash, Superman, Green Lantern, Wonder Woman, Aquaman, and Batman could standing next to the president and guys in shirts and pants and not look silly.
Not much worry about face time I think, so you don't have to worry about Flash, GL, or Batman having to take off their masks to show the actors real faces.
And it would set it apart from the Avengers live action movie. People will be less likely to say DC was copying Marvel's Avengers with their JLA film if the movie is animated.