Originally Posted by
godisawesome
And that's why I said "more ruthless" on Demona - Demona was effectively one of the multiple candidates for Big Bad the show had, even with her anti-villainous nature, complex goals, and sympathetic backstory. She could match being an ally one episode with randomly murdering dozens of people frozen as statues the next - ramp up that villainy a bit more, and you've got a counterpart to Leviathan Talia.
And it's the cool mix of heartbreak, pity, and disgust Goliath has towards Demona that I think is missing from Bruce and Talia; we need to feel Bruce's sense of loss at Talia no longer being someone he could be with and how that collides with her current form where he could never be with her again.
That's also how I think you differentiate her from Catwoman; Selina's someone who, even at her worst, is still by and large tolerable and useful to Batman in a strategic sense, so that colors their interactions all the time, and keeps her on the table as a romantic interest, and if Talia was once a "better" match for Bruce but is now someone he has to stop and can't even let influence Damian too much, that's an opposite extreme.