Having a Superman with seriousness, sadness, and depth is a quality that came to pass in the modern post-1986 era.
Thats certainly reflected in Superman Returns. In fact, some critics say they take the film too seriously.
The fact that Donner (father of the Superhero comic book movie genre) took it seriously rather than tongue in cheek is why we are enjoying movie franchises like X-Men, Spider-Man, Batman, Blade, etc.
Thank God that critics are critics rather than directors and producers.
This movie certainly does combine all elements of the Superman mythos throughout the ages; past, present and future....yes, future....wait and see.