Yay another thread about full voice acting for everything in the game.
TLDR; No, thanks. Let's just keep it to the main characters in the story.
As much as I've enjoyed the voice acting in games like Mass Effect, Dragon Age, and Heavy Rain, when I take a look back it wasn't that I enjoyed that everyone can talk, but more about the emotions that was showing in the main characters of the game which does not always become as apparent in text. Characters like ME2's Tali, or DA's Morrigan, HR's Ethan Mars, or even minor characters like the Witch of the Wilds in DA2. Voices there helps build the character personality and player attachment.
For me, voice acting adds immersion to the world. Such as main characters banter like the one from DA2 can reveal more about their personalities and group dynamics that you won't get with text unless if you run into a cutscene. However, I feel sometimes it cheapen the experience (E.G. Elder Scroll games), such as the cheezy lines from NPCs when you stab them in the face. Or your generic towns people with their banter, which sometimes repeats over and over again about your adventures.
There are at least two main problems with mass voice acting. First is the quality, you can't always get top notch actors for all the roles due the large range of characters. (E.G. Skyrim
http://extra-credits.net/episodes/skyrims-opening/ http://www.youtube.com/watch?v=P3TjgTi0pd8) Second, reusing the same voice actor again and again would create a rather uneasy feeling as you meet someone new but heard their voice before.
There are other games where voice acting plays a large role. Such games like Portal, Bastion, or Stanley Parable narrations. However, since I doubt FFXIV needs or even wants narration, I think we can safely omit that.