I can't say anything other than I agree with you 100%. The episode is awesome when it's dealing with the Sci-Fi plot. My favorite scene is with the "split" Data trying to dump the antimatter into the fissure or whatever it was.
The whole romantic subplot was pretty bad because from the beginning we knew it wasn't going to go anywhere for the exact reasons you mentioned.
And yes, that costume was horrible. I kept thinking "why is this lady in her pajamas the whole episode?"