There's nothing about Harper that grabs me. I still don't feel that she's moved beyond 'sum of x traits expected of batkids' into an actual character.
A mary sue is basically the realized fantasy avatar of the author (ie. Winick's Jason Todd or Simone's Batgirl). Unless Snyder has some fantasy about being a teenage hacker punk girl, mary sue is not appropriate. Anyway right now, she is nowhere near the levels of walking plot device that was Damian, so I don't know why people are twisting there whities over it. Do you only get to be an accepted plot device when you come from Batman's loins?
Can we stop throwing around fan fiction terms haphazardly? While you may not like her, and you're perfectly entitled to that (wrong) opinion, she's not a Mary Sue. At all. In any way, shape or form.
If anyone in the Batverse is a Mary Sue, it's Batman himself. Lay off it already.
I got the contrived character that seemed to good to be true part of the definition, but I always thought it was someone that was above reproach too. Someone who's actions could never be questioned because they were always in the right. But since it's such a poorly defined concept perhaps I'm the only one that felt that way.
I forgot to mention it earlier, but after all the disappointment that we had when the mystery guest in Tokyo turned out to be Julia, I would be very surprised if Cass doesn't show up when Tim's there.
to me a Mary Sue is a character who always has the means to be better than anyone else. Exactly like Harper "I'm not even a character" Row. Unlike Damian, she still has to show any form of character development. Theb lue bird thing, save for her having a costume and a mask, wasn't any indication of that.
Batman may be the batgod with some writers, but he certainly wasn't one recently, see forever evil for instance. and he's certainly a flawed individual.
On the other hand, HArper Row is so cool, so smart, so kind, so protective to her poor brother, so all heart, so well trained, and she can trail both Batman and Red Robin, etc....