Having enjoyed the first WoW comic relatively well, I was looking forward to this new collection coming out in HC format. Having read the comic now, I'm not really sure it was worth the wait.
The book itself is about 170 pages in length, and it definitely suffers from the lack of pages. Much of the action is muddled (a complaint echoed in the first book as well) and it feels like the plot and script is just an annoyance getting in the way of the artists wanting to draw really high action scenes.
The main storyline still revolves around Varian Wrynn - whom we met as Lo'Gosh in book one - attempting to reclaim the throne of Stormwind. However, there is an usurper who looks just like him already in Stormwind. There's some sort of mish-mash with Defias and Dark Iron Dwarves mixed in, but when you boil it down, this is the story that's supposed to go along with the Onyxia raid. There's also a half-hearted attempt to keep a side story running with Broll Bearmantle and Valeera Sanguinar (Valeera essentially plays the roll of a drug addict, and Broll her "AA Sponsor" trying to keep her clean) but it's only mentioned when convenient and used as a plot device rather than an actual storyline.
The art is still very clean, but it feels like a step down from Book One. The pencils and inks feel a lot looser and less detailed, the lines much thicker, and much of the slack is left to be picked up by the colorist (to be fair, the coloring is gorgeous). Also, as mentioned above, the layout is very poorly done - you'll often be looking at a scene that is the middle of a giant battle, some critical event happens that the characters are all yelling about, and you'll do a double/triple-take on the previous panels and still have no idea what supposedly happened.
Book 2 is worth getting if you're simply looking to finish up the story left in Book 1, but on its own neither the art nor the story is really worth the $20 cover price.