Johns' use of TKJ for BOOSTER GOLD was actually the first I could remember seeing that panel in a while, or even really seeing any reference to Babs in terms of her loss at all... and that was in a title that really had nothing to do with Babs. Neither she herself, nor Bruce nor Dick, had referenced it for some time that I recall - I think not since the NIGHTWING annual, in fact. Seeing it in BOOSTER GOLD was actually kind of a shock to me because I'd gotten used to the Bat writers having finally mostly moved on.
But then DC decided to make Babs Batgirl again - which okay, is only a "theory" but at this point, given the evidence, it's a "theory" the way evolution is a "theory" - and just like that, it's Suicide Squad Babs all over again, freshly traumatized, mad at the world, trapped and miserable with her whole universe consumed by the loss of her legs and her confusion about how to cope with that, hyper-romanticizing her time as Batgirl and convinced that her life is over now that she can't be that anymore. Basically, over the last twenty years, she got over the shooting by becoming Oracle, and this makes Babsgirl impossible; the natural solution was to destroy those twenty years of character development and have her get over her shooting again, but this time by reclaiming the Batgirl mantle. Hence, the ending of BIRDS and everything Babs has been part of since: a vigorous revisitation of all the pain and misery of the shooting in preparation for resolving it by restoring Babsgirl.
Except, someone finally got it through their thick skulls that Babs-as-Batgirl post-Oracle is Not Okay. So they did a really obvious abort, gutting their mini and delaying and reshuffling their BATGIRL launch. Which is great.... except it leaves all this sudden Babs!angst without a resolution. They shoved all that anger and loathing and pain back on her to give her a reason to do whatever it was she would have done to get her legs back, but now that's gone, so it's all just... sitting there, making her bitter and lost and cold like the last twenty years never happened, and this is the character everybody else has to write now.
Expect to see a lot more flashbacks to TKJ in the future than you would have had this Battle for the Cowl bullshit never come up.