Why did they change all the voice actors?

[Remus]

Use japanese voices, problem solved.

I find it funny that people say Japanese VA is way better, but the japanese players themselves think its not and listen to English voice actors because it sounds better.

On-topic: I believe it got changed because maybe those voice actors couldn't come back again for certain work reasons else where. Being a voice actor for a MMO can be a bit tough because you need to be coming back every major update and this could cause a bit of stress when they need to do other voice over work at the same time. I don't know if this is true but my theory.