The island episodes that drag on do so for one very good reason, they don't belong there Likely they would have been 2-3 episodes tops, just so Blue Noah could have been found, and then right on to Africa (sans the 3 episode interlude there), and the epic ending. Unfortunately, Gainax fell into pressure from the network to extend the shows run (as it was popular), Anno got pissed off & left the company (just as he did with Kare Kano a few years later), and someone else filled in those island episodes (hence the lower budget, and random stories). Taking that into account, the original plotted Nadia stands much stronger. Be you an Anno fan or not, that man know's how to do epic endings that bring the house down. Definately one of my all time favorite director's.
As for the movie, that wasn't even done by Gainax...an I think characters named "fudgy" have been banned from all anime forever thanks to that horrible piece of garbage that looks ilke it was made here.