It's like a song to Marie on that stage, even without Marie, Per Gessle I believe intentionally left the female part silent, instead of letting the two vocal ladies replace Marie. It made the song much weaker but he just willingly accepted it like that. Marie R.I.P.
It doesn't sound good because the song was written for Marie's particular voice. Both women on stage have their own unique pitch, one that would fit another type of sog but this particular one needs a Marie. The song is good, it had the potential to become a hit but unfortunately it doesn't fit. It's like trying to prepare a sol y sombra and using pepsi instead of coke. I respect Mr. Gessle but he has to find another formula.