Also I don't buy into the idea that 'barbra's presence brings sales' I don't think any bump in sales due to her is all that meaningful, if it did then she would have her own title, Barbra outside of the initial new 52 hype has never really sold well, especially considering the promotion she gets which includes consistent appearances in popular animated media, she was getting outsold by redhood (which was another dumpsterfire considering the hype around his character and the great appearances in games and animated movies), redhood was also selling terribly, barbra sells merchandise like hot cakes, she doesn't sell comic books well, Cass does a better job then barbra as far as selling comic goes
To begin with why are we pretending that sales matter all that much? Dc comics is a IP farm, Arthur never sold that well and kaldur sells worse(seriously if nightwing started doing Below 15k numbers then you might as well let Bruce blow him up) yet they keep them around because that's an IP that they see potential in, Nightwing has consistently outsold Batgirl yet Batgirl gets a movie and Nightwing doesn't because Batgirl is an IP they see potential in, so it has never been about sales as much as it has been about greater relevance in dcu, any relationship that grounds dick in one place is limiting imo, dick doesn't work well with being grounded, that is barbra's thing not Dick's, it's the reason why I've never seen the appeal to their relationship, dick is way more exciting character when he's not grounded in one place physically or mentally, which was why Grayson worked so well, it gave dick a stomping ground that wasn't influenced by Batman but also did not make dick rooted in one place, it also solved the 'secret identity/job' problem, seriously outside of him running a circus everything he has done is lame as hell