I'm in the camp of people who don't know what a fully voiced Tav means. Right now, Tav talks occasionally, which seems okay. The two available voices don't fit a lot of characters, but whatever. As long as Tav doesn't talk too much, it's fine.
I do notice that Tav doesn't join in on the banter. It's always the companions talking to one another. Sometimes I wish Tav would join in. I wonder how that banter will work while playing one of the origin characters.
Overall, I guess I don't care about more Tav voice over.
Tav reactions can be a bit much, like the slight smile when someone offers a compliment or a thank you. Tav seems so childishly proud in those moments. It doesn't bother me though. I've gotten to the point where I appreciate it, even the recoil on the nautiloid in the face of a change at the pull of a lever.