Originally Posted by Jordacar
Didn't Salkind want to bring in Supergirl for part 3 and WB shot him down?
According to the idea, that the producers brought out at the time. Kara was essentially going to be Brainiac's daughter, fall in love with Superman and fight Brainiac in the end.
Mxyzptlk is involved about mid-way through the second/third act.
Frankly, I'll take what we got. It's not perfect, but it's solid on the Superman front and it's a fun movie.