I have beat darkmoor already, but is it a side world or a major world? it only has a few dungeons and no quests other than talking to some one, or going to and in a dungeon, and doing a dungeon, so that makes me think its a side world. but you have to stop malistair the undying and turn him good and get him on the other side with Sylvia, which makes it sound like a major world. so is it a major world, or a side world?
That's a difficult question. In my opinion, it's an extension. Just like Aquila, or Barkingham Palace. It isn't really a world of it's own, because it's really just one large area with a few dungeons. It's not a main/major world because, as far as I know, there's no prequests, and it isn't required to progress through the storyline. It also can't be a real world because there's no access through a spiral gate, and the only way to get there is through Wizard City. So to restate my answer, I believe it is an extension.