Well, having purchased the Blu Ray Anthology yesterday, I quickly went right to the gem of the set for me, and that's the Return to Krypton sequence.
Firstly, it is 100% completely finished. From the score to the visual effects, totally finished.
Secondly, it's going to break your heart that this sequence is not in the film because it's eerie as hell but kind of beautiful.
If I had cut this film, it would've went like this:
WB/Legendary Pictures/DC logos then right into the opening text that summarizes Superman to the audience. After that, fade right into this sequence. When Superman finds the coordinates for Earth and the spacecraft zooms past the camera, I'd lead right into the opening credits but as they were originally planned with the credits inter cut with Daily Planet clippings of what's been going on since he's been gone, ending with a visual of the "Why the World Doesn't Need Superman" article by Lois.
When Singer's name shows up as director and we smash right into Earth, I'd fade right into the starry night of Smallville and the house of Kent as we pan down to the Kent farm and then go right into the scene of Martha washing dishes, when suddenly the house starts to shake.
That opening would've been perfect.
When Kal-El sees the destroyed crest of the House of El on Krypton, it's a great moment and Routh sells the hell out of that moment.