I'm not a big DC guy, but don't they have these universe resetting events like Infinite Crisis or 52 where some cosmic change merges realities? Are any of those stories any good? If so, I'd use it to take the best of what they currently have across TV and movies and dump the rest, or just scrap it all and start over. The roadmap is laid out: you start with some character building solo movies focused on 1-2 solid heroes and gradually build up to team-based movies or 2-3 guest stars to introduce new characters. Make it fun, but serious, and integrate everything into a larger plot that will pay off over time. Just copy Marvel at this point.
It doesn't have to be major characters either - Dr. Strange, Ant Man, Guardians are not big properties, but all had significant roles leading up to the end. You probably need Wonder Woman & Batman. Swap Supes out for Power Girl. Green Arrow is an easy addition as a mix of Stark & Hawkeye, Toss in Flash or Cyborg or Green Lantern and you've got a great base to build around. Heck, they should build it around Shazam - that's a goofy character that could grow serious over time.
