Well, stellar voice acting is good. Deep voice, fine oratory etc. are part of the charm, sure, sure.
But the fact is... what I remember with nostalgia from BG1 and BG 2 is not the stellar voice actings (today mainly an understandable marketing tool).
What I remember at times are all the little spontaneous expressions and :
* "I need an ale ! Burp !" from the dwarf in an inn (now I say that at times outloud, for myself, without the burping part though) * The guard, yawning, who was so tired (I say that too, in french : Oh la la, je suis si fatigué !") * The nervous, proud and authoritative guard of the flaming fist "I serve the flaming fist !" * The bandit : "So I kicked him in the head until he was dead! Nyeha." * The condescending tone of the nobles saying something like "don't touch me" * The famous "Heya, it's me, Imoen !" * The famous "Life is adventure !" by Coran * The stutterings, all manners of speech impediments, the strong accents... * All those voices around you when you were walking in baldur's gate, without having to interact with people, which were alive and noisy even before you clicked on them... * All the little nature sounds... birds, animals, small variations in music and sounds...
The little things, ordinary things, not literary, but just short, some words, like it is alive, it is real, I can relate to it
I don't remember the monologues of the bosses, though. I am sure there were good and I remember the sound of the voice of Sarevok, and it participated to the aura of the character, but I do hope, for the sake of the fun and the pleasure of the players, that we will find here a lot of ordinary/spontaneous lines, not just literary and nice punch lines...