Even though she doesn't appear on panel in these posts, there was something about Katrina Armstrong I found... fascinating. Gail Simone said was going for a "female Jack Bauer" in Katrina, dedicated and/or obsessed with protecting America in a way all too familiar to anyone who spends time around Bruce Wayne.
I hope Katrina returns in one way or another. If Barbara is going to spend her time mentoring Stephanie Brown, maybe a newer "take" on Birds of Prey could take the field.