I agree that when a situation is vague and the feelings of the character could be a number of things it makes sense for the characters expression to be more noncommittal. However, when I choose an option where my character is clearly expressing happiness or sadness or whatever emotion it should be reflected on the characters face. While in some situations it may be more immersive to have a character be a blank slate for player to fill in, it is equally non-immersive to choose a conversation choice that clearly aligns with a certain emotion and not have it reflected by the character.
There were times when I wished my character didn't show emotion (the scene in the owlbear cave particularly comes to mind) and there were times that I really wished I got to see some expression (the scene when you and Astarion find out the monster hunter is looking for him being one).
Perhaps it would be beneficial to focus more on the npc's expressions rather than trying to show the custom character all the time. That way I don't have to look at that weird closed lipped smile all the time and get to see some emotion from characters, even if it isnt my own. The companion's expressions are so spot on that for me it just totally kills the conversation when I have to see my character. Currently anytime my character comes on the screen I cringe because everything they do just looks so unnatural. If they just don't show my character then I would be able to better imagine the expressions myself.
