Let's face it. DC? Their movies are quickly fading into obscurity, partially due to their own ineptness, but mostly because of their complete domination by Marvel in the box office. But there is hope, as their JLA plans are years off.
1. Bring in Less Iconic Characters
DC has this bad habit of using only their big characters in film. This is more of a hindrance than a good idea. They have excellent characters that could translate well into a movie, but they're too afraid to take the risk of bringing their smaller heroes to life on the silver screen.
2. GIVE US FREAKING NIGHTWING!!!
Seriously! Nightwing is a central character in DC lore! He founds and leads the Teen Titans, teams up with most every other hero in the DCU, and, eventually, succeeds Bruce Wayne in the role of Batman. Not only that, but he helps train such central Batman Incorporated characters as Nightrunner, Azrael, and Batman of Moscow. The fact that he derives his title from a legend from Krypton, told to him by Superman, also leads to interesting prospects for the overpowered alien to have a human touch to his franchise.
3. Deathstroke. 'Nuff said
Deathstroke also has the same basic properties that Nightwing does. Slade Wilson has faced off against every character in the DCU at least once, and during the Battle for the Cowl that followed Bruce Wayne's apparent death at the hands of Darkseid, he briefly held the role of Batman as a non-affiliated usurper.