Sounds like the OP wants to see the manager XD
I think her expresions work well to comunicate the kind of character that she is: not nice. Not all characters need to be nice or liked. Some characters are there to be hated, which is a great motivator. Kagha is not Aerie or Arybeth. The purpose in the story is not to be eyecandy. I think there is a tieflin bard that covers that. Hell, for a sexy female enemy you do have Mintara. So that is already covered.
And for some people, having all female characters be eyecandy detracts from the game and the story in the same way it would detract from the story if we complained about mindflayers not being sexy. Or the zentarim not being nice. To me your post sounds like this: "Oh no! Raphael is not sexy and doesn't smile!". And demons are supposed to be seductive. But it is OK, Raphael has another approach.
Anyway, I do like the variety of expresions and characters and I suspect that I'm not the only one. So I hope they don't change Kagha or other female characters to a blander and more boring version.