I think it is not a case, when you compare isometric RPGs or 20 y.o. RPGs with a game where all the dialogs built through cutscenes where your character show it's emotions, etc, and the game has very good instruments to show us much more of a character with voice+emotional reactions. Look at the companions. I am confident that all of them wouldn't been as much popular if they were silent as MC. So that's a big deal in particulary this kind of a scenery work. Text is a great way to deliver char's charisma, but not in the all types of RPGs.

"My understanding is that having 2 voice actors (one male and one female) for the player character including all dialogue options is not prohibitively expensive at all, particularly with the budget of AAA games that BG3 has."

Don't forget that DnD has NINE alignments and all of them are different. So even if there will be only 2 voices, they have to record different voice reactions to the same situations.

Actually, i don't think they will add full voice acted MC, but i'd appreciate this :)