I'm sure that the reason for point n.1 is the enormous volume of voice acting and face animation that would require.
With voice acting only, it would mean recording every single dialogue option by a dozen different voice actors. Then you would need to animate all possible faces of all races and all genders for all these lines of dialogue.
Sure, technically it's very possible, but in practice the amount of work it would require is too big. And it's an RPG, so the amount of dialogue variety is more important than voice acting.
