That their relationship is not and will never be a romantic one. The only big screen adaptation of Batgirl that doesn't portray her as a potential partner for Bruce is freaking
Batman and Robin. I want this movie to make sure that no one comes out of the theater having weird ideas about what kind of relationship these two have.
That's why it is my opinion that Babs should be significantly younger than Bruce. Well that, and because I don't want another large adult Robin.
Eh. The only reason it's not a thing in the main continuity is because she's with Dick in that one and both Bruce and Barbara are so fed up with each others bull**** to make it a thing, but there are plenty of other continuities where that's not the case and she's a potential partner for Bruce. Also, her relationship with Dick Grayson is not really that important for either character to say it /must/ be in this continuity too, you can write them both just fine if they aren't together.
Because it's not a paternal relationship, her relationship with Bruce and the impossibility of it being anything platonic or romantic in any circumstance on canons other than the main one is not something as set in stone in the overall mythology as his paternal relationship with Carrie Kelley and Cassandra Cain because Bruce has never seen Barbara as a daughter and she has never seen Bruce as a father.
Heck, even in main continuity... Cassandra Cain looked at Barbara as her mother and Bruce as her father. Especially in her times as Oracle, her relationship with Bruce resembled more of bickering workhusbands/workwives than anything else, so that leaves some room open to change in other continuities.
The very fact that he doesn't look at Barbara the same way he looks at Dick, Jason, Tim, Damian, Cassandra, Carrie or Stephanie opens possibilities in the elseworlds when they're a bit closer in age or aren't tired of each others ****.
I'm fine with whatever Reeves wants to do with their dynamic, whether it's to just make them allies, imply something platonic, or whether it's to make her as young as Dick to make it impossible to ever be something romantic between the two. Her relationship with Bruce is not so set in stone that you can't play around with it in different adaptations. I'd just prefer her to be a young adult as I think that'd make it easier to incorporate her into the story, but if Reeves finds a way with making her a teenager that's fine too. Also, even then if you make her a young adult that doesn't make it impossible for them to just be friends and allies, y'know.
I know TKJ left a bad taste on everyone's mouth but I'd argue the problem wasn't inherently the idea of there being something platonic, but how out of place it looked in that story. It wasn't a problem in LEGO Batman, or the Batman Beyond days were it was also implied, or in the Thrillkiller elseworld, or in that little scene from Arkham City where she was jealous of Talia. As long as you write it/reference it tastefully it's not a problem and you don't really lose anything on either character.
