Focus less on Batman, more on science fiction/cosmic characters. Flash and Green Lantern movies should take priority over Batman movies and Bat-family spinoffs. Batman should not be appearing in one or more movies every year.
Pit the Flash against the Rogues in a small-scale movie instead of doing Flashpoint.
Make a Green Lantern movie that has Hal, John, AND Guy, AND Kyle, all sharing the spotlight and working together. Set it mainly in space, not on Earth.
Use Superman villains other than Lex Luthor (I love comic Luthor, but movie Luthors are overexposed, just like movie Jokers).
Make a Carter Hall Hawkman movie (not Katar Hol). Carter is human, and his origin is tied to ancient Egypt, not space, so he has less similarity to Superman and the Green Lanterns.
Make a Martian Manhunter movie.
Get Clark and Lois married already.
Do a Wonder Woman movie set in the present day.
Make proper use of the Suicide Squad by pitting them against a political enemy (ie a country, like Russia or Iran, or a South American drug lord or a terrorist group). Use a fictional country like Qurac if you have to, but DON'T pit the squad against a villain that has no similarity to a real-life enemy of America. David Ayer completely missed the point of the Squad by making them fight a generically evil witch in an empty American city. (And yes, I've read The Nightshade Odyssey.)
Adapt non-superhero characters like Jonah Hex (it shouldn't be hard, just do a Western) and Sgt. Rock (it shouldn't be hard, just do a WWII movie) to film.