I have never in my entire life associated amazing story or voice acting with Final Fantasy. Ever. It's horribly full of plot holes and miracles and all that. It has always been this way. Same with dialogue. Didn't feel that WoFF was any bit worse than the other games in any of those regards, particularly when considering it is supposed to be a more 'fun' game than the others. When you add that in, I dare say they did better than any of the other FFs, with perhaps the exception of FFV.

EDIT: Also, I'll happily say that all pre-voice acted games had, in retrospect when playing them, shoddy writing. Not dumbed down? Eh, perhaps not, maybe? But no better than WoFF for me.