DC Comics has zero power over what characters are used in the film and animation departments of Warner Bros.
Then what about the Bat-embargo or Carlin's hold and control of the Superman. That was during the Kahn and Levitz eras, but they clearly had influence and sway and the Bat-embargo was clearly en-acted on a level above editorial and likely at a publisher level.
Also the reorganization you mentioned -- the move from NYC to Burbank, CA and the staffing changes that this resulted in -- came from a corporate initiative to closer align DC publishing with the greater (and more profitable) film/TV division of WB.
What you are talking is a series of policies that were enacted across the span of a decade starting in the early 00s. Regardless of his current standing, I'm referring to the '10 promotions and also the recent defanging of his co-publisher at DCE.
Edit: And of course this goes back to the entire issue of how he ended up hired by DC in the first place.