every film was running way late due to effects. people at weta (the only reliable source i can think of) are always complaining about how they don't have enough time, they work to hard, and its never goign to be any good.
obviously they were wrong twice, so i don't see any reason for them not to be wrong this time.
I can say this because up until a year ago, i lived in wellington, home of Weta, PJ and LotR. it seemed like half the peopel i knew were working on the film, almost all in the digital effects section.
don't fret children.