Here's my 2 cents on this topic. I have played a game that does this (GW2) and I did like it, at first. That is, until I made a different character with a different "personality" I had envisioned, and the voice was exactly the same. It really ruined my immersion, and I could see the same thing happening in ffxiv with fantasia and alts, etc. I don't think it's a good idea.