This would double the length of time of patches, and due to voice contracts we would most likely have voices changing every few patches.

Lets not forget people were jarred with the Heavensward voices for a few characters.

That said I would be all for a voiced MSQ. But honestly...I think MMORPGS need to stay away from fully voiced content as it tends to draw out development time, cycle actors at an alarming rate, increase costs, take resources away from new content, and in the worse case recycle actors.

Look at WOW, who wasn't voiced by Chris Metzen?
If you ever log onto ESO you will die of laughter when you realize they had maybe 6 voice actors.
I've met Dark Elves who share the exact same voice with Argonians, and Nords.
I also met a family that had the exact same voices. All the females were identical, all the males were identical.
Talk about taking after your parents huh?