I'd take Jan Jansen, Coran or Hexxat over Astarion in a heartbeat. Astarion feels like parody with his "evil vampiric ways". The vampire storyline isn't doing it for me either. It feels like an afterthought. Twilight fan fiction rather than a meaningful take on vampirism that would have meaningful game mechanical implications.
And BG3 desperately needs more light hearted adventurers like Coran or Ajantis to balance out that ridiculous snowflake cast. But I fear they are only going to add more snowflakes and revel in space hamsters.