If you think there is a problem with the quality of his writing that's fine.
Sure.
I don't quite get why we compare Minsc vs Astarion. Minsc is more of a comic relief character... Astarion is chaotic evil(?) vampire. Quality of either aside, I do think it curious that someone brought Minsc to the defence of Astarion. Is Astarion supposed to be a comic relief? Is how bad he is in concealing his vampireness a joke in itself?
It might be me, but I just see why would it be a compelling to have Astarion around - unless BG3 aimes to be a Cohen's Borthers style adventure following group of idiots to their demise. Minsc wasn't bright, but you could trust him to have your back - if he was annoying, he wasn't harmful. Astarion will stab you and everyone else in the back and is bad at doing it (story wise). That's a terrible combination. Even if I would play an evil character, Astarion simply isn't someone useful.
