When something is a character's dominant portrayal for long enough, it ceases to be OOC. Diana doesn't really have that problem because, as extensive as her history of bullshit is, it's fairly inconsistent bullshit. No two writers get her wrong the same way, so no wrong take can take hold. Bruce's dickery is well-established and very consistent across multiple writers, titles and years of publication.
Beyond that... When Diana is written as a moron, it makes her book annoying to read and her character look stupid. When Dinah is written as an incompetent dupe of Ollie, it makes her book annoying to read and character look stupid. When Dick is written as a waffling jellyfish, it makes his book annoying to read and his character look stupid.
When Bruce is written as an emotionally stunted, controlling jackass, it hurts Babs and Dick and Tim and especially Cass, it fucks over the Justice League, it gets characters killed (Steph, Ted), and makes half the DCU look twisted and foolish or cheap or overtolerant or like an abused spouse who comes back for more. It's not quite as easy to overlook or move on from once a good writer hops on board, when it leaves other characters bleeding in its wake in their own stories (or cuts those stories short). Particularly since the good writers are generally the ones doing it, which gives their stories traction ("Who is Wonder Woman" is a shit story on its own merits even if Diana had been a completely OC; "Bruce Wayne: Murderer" was an interesting crossover that had a lot going for it and good reason to be called back to).
And actually, I did throw Cassie to the wolves somewhere along the course of Johns' TT run. I genuinely don't think of her as the same character, any more than I think of post-Crisis Bruce as the same character as Bronze Age Bruce or DCAU Bruce.