I think this would be interesting if they implemented it, I also don't think it would be completely impossible for them to do in a definitive edition or something, because as far as I can see in-game, nothing about Astarion's character directly conflicts with this narrative about what was going on with him before he was a vampire. The game doesn't really talk at all about what was going on with Astarion before as-is. It's possible it was cut, but the hole wasn't really patched with much else, and could be put back without much effort.
Correct me if I'm wrong but currently in-game, about Astarion's past we know:
1. he was a magistrate
2. he was 39 when he died
3. he was beaten basically to death by gur
4. cazador 'saved' him
5. he doesn't remember much (ie if you ask him what color his eyes where he doesn't even remember)
It isn't too hard to imagine about the last point he possibly knows more than he's letting on, it's also completely possible that after
only 39 years of life and over 200 years of torture, also having a 'death' where you got beaten within an inch of your life,
that he really doesn't remember.
For me, it seems like all they would really have to do is add back in the Cazador explaining things dialogue, maybe some findables referencing it, and then the reactivity to that information, and everything would be as it was, except for the slight rewrite or softening of his EA character. It even seems to me like this might *still* be his backstory, it's just not said or talked about in the game. Which, leads me to my imagining it could be fairly easily added back.
I could totally be wrong, or misunderstanding something. Wouldn't be the first time lol. But maybe this makes you feel hopeful?
Edit: And that it's still in the art book? It seems likely that they are working on it like the rest of the stuff.
