Is there some law that forces people to like a game certain character's from even if the game sucks balls as a whole? You don't have to dislike every character if you hate the game.
Proof: Some people like Sonia but hate Legends because it didn't do her justice. Same is the case here. The sisters were great characters, but por downplayed them a lot barely even showing them, giving them some cliche "vampire" lines, then eventually brushed off completely once they're cured to force the much unneeded Dracula in.
They were supposed to be major villains, but their roles were like those of small minions nobody mentions.