Yeah I have the same general feeling, at least regarding the importance of the faces, when so much of the presentation is this cinematic close up hehe. You're probably also correct that it would be near impossible to satisfy everyone absent some sort of slide construct. I wish we could basically have 10x10 rows and columns of broad facial morphology covered, which had like a basic organization by shape and major features sorted, then allow the player to slide out from there.
I also think it would be rad if we could stage and capture a portrait in game. I mean the game already utilizes gestural animation in cutscene, and you can screen cap what is essentially a portrait. We just can't do that and save it out in a way that the game can utilize on the fly. I would love to see it handled more like DAO, with the lighting and expression and such but dialed up to 11. I mean for me that would be the BG3's answer to BG1/2s custom 2D portraits. A 3D portrait suite using the models in-game, complete with outfits and lighting, camera and gesture control, the cap to save out portrait at Headshot, Bustshot. A full body shot for the Char Sheet would be awesome, if we could make use the attack and spellcasting and sneak type animations. Basically a mini unreal type scenario, but adapted so it could be used by a more general audience.