Well, we see it differently.
I think Astarion is one of those who will use your help if you are kind to him, but sooner or later will betray you. I also don't think the source of his evil is just vampirism. And the problem is that it's a CHAOTIC evil, not any other subspecies. This is not a habit. Not an injury. Not a law for him. This is a kind of entertainment, pleasure. In fact, if you try to fix him, you will destroy the basis of his personality.
A lot of people think he's a victim of his master, I think he's always been an asshole. And if that's the case, then fix a 200+ year-old asshole... well, it looks very illogical. For me ofc...
But Yes, this is just my opinion. If they give him an arch of redemption, I just want it to be logical, not just because the fans want it to be.
I just can't see him as chaotic. He has a law: "stay alive and stay on top no matter what".
That just strikes me as neutral evil, that is to say, self-serving dialed up to 11. The reason he is not lawful evil is because he will always put himself first, and the reason he is not chaotic is because he is fully committed to his own freedom and survival.
I think we will get a redemption arc IF and only IF Astarion manages to forego either his desire for survival or freedom. That would naturally result in him dedicating himself to a purpose outside of himself. It would break his internal vicious cycle of wanting to be alive at all costs pushing him towards enslavement and enslavement pushing him towards wanting to be free.
This is very hard to write however and I'm afraid that Larian may not be able to handle it.
Or maybe they will surprise us and pull of something genius.
Or maybe he really is irredeemable.
I'm very hyped.