The English dub cast is also being reunited for the movie (or already was, I guess) and they were pretty good. Watch the movie in OSL subs, then watch it in English to hear all the loudness from 5 channels (with a sub channel).
I didn't mean to imply that the director didn't want the OSL in 5.1 but that they weren't given a 5.1 OSL and won't remake it for the DVD. That's what I heard.