I have yet to see someone come up with this, so here it goes:
What if you could upon character creation decide your character's personality traits, just like you do when filling out a dnd character sheet? The thing is, origin characters are very expressive. Even without understanding a single word they say, one could make out their personality through their body language. Whenever I make a new character in BG3, I have in mind their personality, but it falls flat when they have no body language to act like it.
So along with other things, you could decide your character's temperament and that would change their base animations. You could decide your character is timid, so they always scrunch up their body, fold their arms, and often look away. You could decide your character is super confident, so they don't get into defensive positions when threatened but instead smile at the challenge, stand proudly in conversations, and look people in the eyes. Maybe they're calm? They stand up straight, don't make many facial expressions, and don't react strongly. What if they're energetic? moving a lot, smiling often...
I don't know about others, but I would really appreciate having these options and feel like I have more control over what my OCs are like.
