Honestly, I tend to disagree with even seriously making the assertion that it is squarely a "DC" film at heart.
- Is it set in Gotham? Sure...
- Are the Waynes in it? Sure...
Past that, how much of a "DC" film will this wind up being?
- Is Mad Hatter going to show up?
- Will Arthur wind up in a vat of acid at some point?
While I can see trying to lump them all into "Comic Book" or "DC" piles, it's not like this film will be one where folks say "Why, yes. This is clearly a film along the same lines as Suicide Squad."