I found this issue boring and poorly written.
Batman gives up and asks the Owls for help (great writing here, the owls sure are powerful since they are the first people Batman goes to for help), and then somehow the villains just agree to cooperate. And of course Harper is able to keep up with the rest of the bat family despite having no training or experience.
I completely agree. While I don't have a problem with Batman going to the Court for help, I though it was utterly ridiculous how (1) all of our high-profile villains suddenly ended up on the same street (seemingly for a goofy group photo) and (2) how quickly they all decide to help Batman. The story had great potential until then.
Regardless of whether the joker toxin was threatening the villains I just think it was silly and hasty writing.