Understandable.
I think the main problem here is that it's a group of assassins, and the primary way you can use them is to have them kill a bunch of redshirts. Which first runs into the issue with killing people in superhero comics, second more points to something in the detective vein, and thus more suited to Batman or Black Canary or even Plastic Man.
On the other hand, Fontana used an assassin squad in her run, which worked reasonably well, even if the actual arc wasn't centered on that group of hitwomen.