Hmm, opinions that come to mind are
Purely hypothetical, but if a storyline had Barbara stop being Batgirl, I'd be okay with Cassandra, Stephanie, or someone entirely new taking up the mantle. I do think there can be multiple Batgirls simultaneously.
Harper Row wasn't a bad character, it's how she was handled. Much like how Geoff Johns keeps writers from using Shazam or the Justice Society, Scott Snyder and James Tynion IV kept writers from working with her, which I think is why Batman and Robin Eternal was so convoluted (among other things); it had to stuff entire storylines into a story that should have been about every Robin. I'd love for someone else to bring her back, eventually into a vigilante role.
I enjoyed Tim Seeley writing Dick Grayson out of suit, and I like Shawn Tsang, she was interesting and a good foil (and romantic interest) to Dick.