Personally I would appreciate some of the main NPCs (particularly companions) having some of their key dialogue and opening lines voiced (assuming done well ;-), but would be really, really disappointed if the protagonists were voiced.
I much prefer silent protagonists as I find that voiced lines confer a specific tone and meaning to dialogue that limits role-playing flexibility for different characters. I can easily accommodate the cognitive dissonance that occurs when the intended tone of a written line of dialogue doesn't match my role-playing interpretation of that line, in return for the flexibility, breadth and nuance in role-playing options within dialogue that comes from being free to interpret tone and meaning.
For example, a dialogue option may read as "Oh yeah, so do you want to make something of it then?'. This may be intended, as written, to be a snarky line that accordingly results in a hostile response from the NPC you are talking to, yet if it is voiced then it can only ever be a snarky line, and furthermore will be imbued with the personality of the voice actor. If unvoiced I am free to imagine my character saying this line, with my character's personality, in a diplomatic or humorous or disinterested or offhand way etc (all very plausible ways to say such a thing) and can easily interpret the hostile response from the NPC as a misinterpretation of what I meant, or them acting for other reasons despite my conciliatory tone or based on some other motive of the NPC, according to the context of the situation. After all, a lot of real life discussion is miscommunication and often others actions are not readily understandable. Sure, sometimes the mismatch may be so glaring that you just have to hand-wave it, however I consider this a small price to pay for greater roleplaying freedom and player agency.
Or to put it another way, voice actors tend to give far too much character to MY character.
Voiced is fine for set protagonists, can be great even, but not so much for blank-slate protagonists imo, which I am under the impression is the case for Original Sin.
