And that's basically what makes Astarion's a bit unsatisfying, imo, it's neither personal nor meaningful - and at least for me, multiple hugs can't fix that. Though it would be nice if you could ask him to to the rounds with you as well as hug him when he rather wants to stay behind. ^^
Still if given the choice I'd want to see that stupid "I will always protect you." line replaced or supplemented with one that I'd rather click. But that's maybe just my personal pet peeve.
I agree with the meaningful part- perhaps not in the way you mean? To me I get this feeling that the epilogue doesn't come across as... Astarion-y, at all. I only got that impression from his interaction with a friend Durge, and what he says when Cazador's still alive and kicking also reminded me of his sadder moments in the game, at least. The rest feels so very bland I can't see the character shine through all that much, only because he's visually there and making the same sounds.
The I will always protect you line is uniquely fucking awful. I'm in general personally opposed to modding my game to overwrite the canon- but that's something where I absolutely would, because it seems like such a non-sensical thing to add that actively works against the story where my brain automatically assumes it's not canon at all. He does at least seem irritated by it, but not nearly enough, and just the fact the line is where it is feels like the game thinking that's actually a perfectly okay thing to say.
