MM Hell has tossed up a review of Throne of Oblivion, giving the Shadowbane expansion a disappointing overall score of 5.6/10. Their conclusion:
If you are a die hard Shadowbane fan, and have been able to put up with the ongoing incompetence and all other issues, you should of course get Throne of Oblivion as it adds a good share of new toys. For everyone else, nothing has changed. If you are a mastermind of player versus player combat, and want to bash heads on a massive scale, Shadowbane might be your game. Despite the high appeal of the story of Shadowbane - you will have to look very hard to find any of it, as there clearly is no focus on story in this game. So if you're after slaying dragons, or anything that does not involve player versus player combat, Shadowbane is only second, third, or actually fourth choice.