I personally am one for both but to have a voice behind a character gives that character a form of soul, a being. It is not about just reading the quests or seeing the what needs to be done . Many people just click process or agree to get the quest and see what they need to do but from my side. I appreciate voice behind anything.
Take into consideration how many people come together - what would it be like if everyone had nothing to say but small text messages or speak with one toned voices.
It would be awsome to see the Sons of Remus have a voice in that armor, To see the royal familes have a bee like tone in their voices, see the senator with a proud yet concerned tone that shrouds mystery and so much more.
It only adds color and life to the characters, that when a plot takes turn and there is no character but a voice, we as the playing community will somehow recognize the voice without the need of a face or name.
It adds a dimension that can only deepen the realism and love for what we enjoy.