I think there's another topic for this, although I can't recall if it was closed or not due to reaching the post limit. There were two at one point, I think.
Anyway, for TES, I don't want it as it was in Fallout, purely due to a lack of variety which is necessary for TES.
If they were to have a variety of voices that would encompass enough of a range for possible characters, I am more open to the idea, provided that they expand on dialogue options in Fallout 4, even to the extent of having a lot of fluff.
My only concern, if variety were met, would be the impact on moddability, even as someone who has not historically used mods. If they upped the scale of the games, in terms of the number of factions, a larger map, more faction dispositional consequences/choices that shape the policies/aspects of the world in a tangible way, expanded upon dungeons, expanded upon dialogue per NPC, and companion dialogue as a whole, with speech consequences/checks, settlement stuff, or anything else that might be something mods would expand on that could be negatively impacted by a voiced protagonist, then I would be ultimately for it.