Gedo Senki came out in 2006, but I hadn’t heard about it. It’s a beautiful production. The animation backgrounds are like paintings, and the music is interesting dramatic. Even the ambient sound, something you might not normally notice in an animated movie, is textured and detailed. This is Guro's first directorship. Maybe it's not as good as his father's work, but it's a little unfair to compare.
The movie isn’t taken from the original Earthsea trilogy, but from a later collection of stories. If you haven’t read the Earthsea books, by Ursula LeGuin, you should. They’re really worth the time. Almost 30 years before the first Harry Potter, there was Ged from the island of Gont. Ill-treated as a child, he discovered he had magic powers, and was sent for a school for wizards to develop his skill and learn to use it responsibly. The trilogy is short. The three books are under 200 pages each. LeGuin also wrote later books, Tehanu, The Other Wind, and Tales from Earthsea. These are also good, but a little darker and more grown-up. I would gladly have my kids (7, 9, and 11) read the trilogy, but I think I’d want them to wait on Tehanu.