Personally, I always felt the countless throwbacks to STM could have been dropped for an altogether new plot. Lex Luthor should never have been after another land-grab plot, but should have deliberately sought out Superman to destroy him, once and for all. Kevin Spacey's performance was also far too reminiscent of Gene Hackman. Luthor is a suave, cool, self-confident and coldblooded businessman. His OTT rants should have been left out. It doesn't suit the character. Kate Bosworth also destroyed the sympathetic relationship that Reeve and Kidder worked so hard to build. She threw it all out the window by treating Clark like dirt. Granted, it's part of the script, but that doesn't matter. She didn't live the part. She felt like a living cardboard cut-out giving her worst impression of Lois Lane. And lastly, Jason. Superman should not have conceived a son with Lois. Period.
But don't let my comments throw you off guard. I bought both the Ultimate Collector's Edition on DVD, and the Motion Picture Anthology on Blu Ray. I love Superman Returns, it's a great film, and I can overlook the points I've summed up, in favour of the bigger action scenes. Like I said before: the plane, my god, the plane! That still gives me chills.