Ok... when I think about it... We're worried about awful voice actors... right? Well, If you look at other Animés such as Nausicaa or Princess Mononoke... even the voice of Rikku in Spirited Away., I don't that Squeenix would screw us over.
I know that the movies mentioned above were made by Studio Ghibli and created by Miyazaki, but if you look at the FF:TSW failure, even that movie had an all-star cast (eg: Donald Sutherland, Alec Baldwin). As E3 closes in and the new issue of Jump magazine with the new info and hopefully the release date, so I'm guessing that soon enough we'll hear who will play these legendary characters..