[@The Kid Lantern] Villains tend to be more lone wolf and thus harder to rally behind. There are probably a lot of villains fighting amongst each other for control of the crime ring in Gotham. Not used to making any big bads. 

My thought with Ivy (dropped the Poison on purpose) was take someone that was traditionally a villain (though one could argue she walks the line in canon as well) and take her back to a point where she could possibly change depending on what happens to her. Her history is against her though so there is quite a bit to overcome for something like that.

I can do some of the canon villains if need be.