I think as a deconstruction he is very interesting. I'm really glad they went with that. I'm not necessarily against the sexy vampire trope- as I consume a lot of vampire stuff and it is quite common as seduction is a big theme for them- but Astarion's seduction in specific was so unbelievably cringe and obviously, painfully, ineffectively fake that when we had it confirmed that was the case and that it was intentionally part of his arc to deconstruct that it was a huge relief.
It was a very nice surprise, honestly, because in EA all I could think was "wait... it seems they're playing his hypersexuality straight, but wouldn't he have trauma from doing all that for centuries" so me seeing they addressed it in full release proved me wrong in thinking they would just never take that part of his story seriously.
The part of him that I mostly liked in EA that made me bear the terrible act 1 romance (a Bad Romance, you could say...) was his almost... joker-like? (doesn't feel a fully apt descriptor but eh) nature and random bouts of violence and his hatred for pity, and they mostly kept that straight... I guess? It's also deconstructed in places, and they mostly removed the scenes where they address his hatred for pity and didn't really lean into his violence except for the Petras scene, so that and the lack of addressing his magistrate past was a bit of a disappointment.
I quite liked the display of vulnerability introduced in the scar reading scene, and they did very much lean into that later, so in that department they delivered. I think that's where the deconstruction starts.
Feel free to intervene, fylimar, if you consider this derailing a bit too off-topic for your thread, I feel like we invade conversations with Astarion discussions sometimes ^^U
