The review makes the book sound incredible, though perhaps a bit too cluttered. The novel is roughly 300 pages in length (I believe) and the first 100 pages covers his childhood from the arrival of the Stormwind refugees in Lordaeron to the beginning of Warcraft III. That covers about fourteen years, and that's potentially a lot of territory to cover!
Still, if it's pulled off well, it has a lot of room to be incredibly awesome. BlizzPlanet says we'll see some interaction between Young Varian Wrynn and Young Arthas, which should be really, really cool. I'd love to see what Varian is like in the hands of a capable author. There will also be a deeper look into the love triangle between Kael'thas, Jaina, and Arthas.
I strongly recommend checking out the review over on BlizzPlanet if you're at all interested in this novel, or even if you're not. He hasn't finished the book, so take is more of a review preview. It made me very excited for the book, so hopefully it'll do the same for you.