Ha, I just was rambling in my post about how much there actually is that got cut out of Suicide Squad where Harley actually is surprisingly well written and more in line with her original version. It's not done by Dini but there's a single issue in one of the anthology books (Legends or Gotham Knights or something) where it's just Batman and Harley talking as they wait for the police and that was one of the first times I realized that Harley is actually the more frightening character.
And the cut scenes, even the ones put back in the extended cut which is like 5% of them, actually tap into this. The Joker is a psychopathic killer who can't control himself. Harley is a super well educated woman who chooses to participate. And it's not because of just some goofy Mr. J! love. That's the cover story.
Which was the point of the comic, logically nothing Harley does makes sense if you accept she's merely been corrupted by the Joker, there's no better version of Harley to appeal to by Batman to save the people going to be killed. The Joker can be appealed to by Batman and often is through some crazy logic.
I can't imagine that's the version we get in Gotham City Sirens, it wasn't the version for most of that comics various incarnations, it's not the version in most of her billed comics, she was it briefly in the Suicide Squad comic when she was the only member of this murderous criminals to actually willingly murder anyone in her way, and it's the stuff Warner edited out of the Suicide Squad movie to the point they had to rip the Joker practically out of the film to keep her character up on a pedestal of fun wacky crime.