I thought Dax was alright, maybe 2.5 to 3 stars. Maybe it depends on how much you liked Jadzia as a character? I know she's not loved around here. Me and my friend loved her when we were younger, as we enjoyed the concept of the worm in her belly, and those crazy spots on her.
These days I can tell that she was maybe the weakest link in the cast, but I still like her somewhat.
Season one is definitely where she was a bit dull, so this episode goes to some lengths to explain just what her deal was. I enjoyed how stubbourn she was in not saying anything because of what happened with Curzon and the wife. It's was somewhat honourable. I agree that Curzon killing someone would have been a better hook, but I suppose we got Joran further down the line.
I understand your point of the episode repeating things that we know now over and over again. I still see it as a brighter spot in the first season, which isn't hard really at this point.