I agree that this is an interesting and important question. I personally preferred Baldur's Gate's dialogue style, but both methods can world well in a game. However the other question is even more important in my opinion. I loke the second option the most, since in my opinion seeing the stat requirements in a dialogue option ruins the immersion for me. I'd rather know that when I try to persuade a person, I have to have either high intelligence, high charisma or speech in order to convince someone, but I don't want to know exactly how hard it is to convince someone. Fallout did this aspect perfectly in my opinion.