From the very beginning, Astarion's writing has revolved around one simple facet: Larian Studios correlating between his being a monster known for being predatory and manipulative, and his queer male sexuality.
No, in the beginning (that is, early access), Astarion's story was that a corrupted magistrate whose downfall was because of his own evil machinations and dealings with vampires. That was supposed to be the twist; the player would first only experience his story from his point of view, and then learn of the other side. Later, as with other companions, Larian scrapped parts of his backstory. I don't think it is even because they changed the character concept, rather, I suspect this is due how barely finished Cazador's dungeon is and how the entire interaction with Cazador is just one battle.
The new animations are the result of Larian's current approach, which has started long ago, and that is catering to twitter posts and fanfictions. Halsin is another example, his act one characterization is as he was in early access, the new additions (beyond his act two quest) is the "daddy Halsin" meme.
