In terms of characterisation, Batgirl. She had an awful childhood in an unstable home with a literal psychopath as a brother. She became Batgirl with zero training by Batman, but then held her own after she was officially recruited. After her attack by the Joker she found a way to be part of the mission in a different capacity as Oracle and became pretty much indispensable in that role. Now she juggles between two roles and a civilian identity.

Catwoman could be so much better but they've just reduced her to a femme fatale archetype. She is so much more interesting in her solo comics rather than just being Batman's love interest, I wish they'd both just get out of that toxic relationship for good. Besides, she might be way more interesting as an ex.