If you're still waiting for something even resembling storytelling competence from
Destiny, you'll have to keep waiting; while
Destiny: House of Wolves introduces a handful of new areas (most notably a new hub world), there's nothing going on that will get you invested. If you remember Queen of the Reef Mara Sov (the extremely rude blue person with the extremely rude blue brother), you might remember that she promised to call on you in the future. Well, the time is now; the fallen House of Wolves, formerly sworn to her, has declared war against the Reef under the guidance of Skolas, who has declared himself "Kell of Kells" and is currently trying to shore up the necessary support to unite the Fallen under his own rule.
So you'll be contacted for a few story missions by Queen's Guard member Petra Venj, and invited out to the Vestian Reef. The Vestian Outpost is essentially the Tower for the Awoken; they have their own vendors, postmasters, cryptarchs, and bounty providers. Like the rest of the known Destiny universe, it's an extremely beautiful place, but in the end, it's still largely an empty and uninteresting one.
So you'll take on Skolas and his Wolves over the course of a few story missions, all of which might take you from an hour to an hour and a half. Some of these take you back to overly familiar areas, and a few give you new areas to explore. Is it enough? Unsurprisingly, no, it's not. But there are a few new toys to play with. Sidearms make their debut; you can assign them to your special weapon slots. Perhaps the most fun addition is that of the Scorch Cannon, a power weapon that fires orbs of bright orange energy; as you hold the trigger, it builds up explosive energy, which is released in a satisfying burst when you release the trigger.
Bungie has added a new gameplay mode in Destiny: House of Wolves; Arena gameplay. When you gain access to the Prison of Elders, you'll have the opportunity to fight off waves of varied enemies under unique conditions for special rewards. Most shooters have included modes like these since Gears of War 2 popularized it. The reason the addition is kind of dubious here is because most of the core game itself was made up of exactly this kind of gameplay; remember deploying Ghost to interact with terminals, only for the Fallen, Vex, and Cabal to conveniently choose that time to attack? The addition of modifiers that switch out between rounds force you to play in different ways, and though the illusion of variety is welcome, it's contrived.