I was severely disappointed in the direction and approach that Singer and his whack pack of fool writers took. The concept of the return is great, but the execution was very poor. I would much have preferred the concept with a Superman not connected to the Donnerverse and definitely would have preferred a Luthor based more on the CEO version.
Spacey is a good actor, and did well with what he was given. That said, I would have preferred the CEO version.
I was very disenchanted with incorporating Superson into the film as well. This was a horrible mistake, IMO. and really neutralizes any opportunity to use Kara in a sequel as we already have Super-Jason. I was very disappointed in Jason, and the direction Singer took with doing this. If Superman had been in space, I'd have preferred he find Kara on Argo than come back and find Jason.
It's hard to swallow Kate Bosworth as Lois. I felt she's a good actress, but too young for the particular role. She did well with what she was given, IMO though.
The talents of both Kal Penn and Peta Wilson were both utterly wasted, as was providing a character like Parker Posey played. I would much rather have preferred Mercy than Kitty Kowalski.
The visuals were amazing. I do give credit where it was due, and the cinematography is great. That said, it was really wasted with the lack of action. It's like, this is it? I was very bored with Singer's approach and feel that a number of directors, and writers could have done the film a bit better justice than Singer. I definitely have confidence that there are more than a few writers here on the boards who could have delivered a great film if given an opportunity.
Finally, I was disappointed with the lack of a segue or transition into the next film ala Batman Begins. This was really done well by Nolan, and not done well by Singer. Singer's ego knows no bounds, and is likely in denial that the film really has underperformed. One thing that is truly sad, is that WB will undoubtedly just continue to throw money at the Superman franchise, rather than bring in people who are familiar with the source material, and not just the Donner film.
Singer should really take a cue from Nolan and Raimi and he could see how to do a superhero film in today's times. They understand the genre in a way he doesn't.