IGN AU reviews Neverwinter Nights 2 expansion Storm of Zehir and likes it about as much as its American counterpart did, giving it .1 point lower than the IGN rating at 8.2/10.
There's a sense of liberation about this design. It's like playing a Fallout game (any of them, really) and just deciding to ignore the story and quests, and simply wander off into the wilderness just to see what's out there. Here, it's usually a cave with a bunch of creatures guarding some treasure; sometimes it's just a solitary building with nothing much to offer; occasionally you'll have to flee at the sight of a monster far more powerful than you can handle.
There's also a sense of emptiness, as if nothing much really matters. Without the import of a main quest to drive you onwards, there's often little incentive to continue to play. Finding cool stuff and exploring, levelling up your characters and forging your trade empire are all rewarding in their own way, but much of the time it's about setting your own goals. In Planescape Torment, you're compelled to play because you want to find out who Ravel is, what happened to Deionarra, and who you are youself, to name just a few questions. Here, all that's pushing you forwards is your own desire to visit the lands across the river to the north or have your warlock reach level 12 so you get access to that spell or feat.