Captain Marvel is an immensely important figure in the history of comics who is often overlooked. Part of this is no doubt due to the fact that his name cannot appear in the title of his own books due to a trademark settlement with Marvel. But a larger reason is that DC has had a lot of trouble figuring out how to use him correctly after making the decision to incorporate him into the same world as their other characters.
Marvel is a magically powered God, who shares his body with a child, and who lives in a largely cartoon world. He's partnered with a talking tiger and his two biggest foes are a nearsighted dwarf and an alien caterpillar with glasses. Thus putting him next to Batman never worked all that well.
Which, made it very strange that DC took this long to publish a story that takes the character back to his roots. But this relaunch could only have been pulled off this well by Jeff Smith, possibly the best cartoonist currently working in the medium. The Alex Ross intro probably says it best, the book is charming. The only fault with it is the story feels a bit like an introduction to a larger story, that doesn't and probably won't ever exist (Smith is starting work on a new self-published book).