The shot from Pazu and Sheeta's perspective when they waking up on Laputa and focus on that one clump of flowers. Is one of the greatest moments in cinema/animation. And it isn't even really animated, just the painting, and how the focusing is timed with the music. And of course, the opening titles are another of these. Watch out for something similar, though not quite as spectacular in the opening of Nausicaä.
If managed to love Laputa just from the dub, then that's good for you, but if you didn't… You may have liked it better without all the corny one-liners, but now even when you watch it with the original soundtrack you will always be reminded of them. At least, that's how it tends to work for me.
PS. I admit that I love the "Get out piggy, get out!" line and wish that was in the original. Spirited Away also has something extra at the end which I think makes genuinely positive contribution. But things like these are always cancelled out by things that are changed for the worse…
PPS. If it's creating new Ghibli fans, and new animé fans, that's the best news I could hope for and I'm happy enough no matter what language it is in.