The story would go as follows. An increased gang violence in metroplise gets Superman concerned and as Clark Kent he and Lois are sent on an assignment to look into it. They soon discover that the gangmembers are getting high tech equipment for some where (this equipment would be like weapons that aren't from earth). The truth is soon discovered that a man named Desaad has been giving these gangs their weapons and it's revealed he is from another planet. Superman attempts to stop Desaad but his minions Mantis and Kalibak fight Superman so Desaad. Several days later large hordes of creatures called parademons attack metropolis. Superman puts a large dent in their numbers but another being arrives who calls himself Darkseid. Superman and Darkseid then do battle.
Of course this is only a summary to give you guys an idea of what I think the new Superman story should be.
Here are the main cast I would pick.
Brandon Routh should defenatly return as Superman. I thought he did a great job in SR.
Lori Loughlin I would cast as Lois Lane. She's pretty, and she's also not to young to play the role and she's a good actress.
Alec Baldwin is a fantasic actor and his voice is awesome.I like Marlon Brando as Jor-el the character needs to be given new lines so he can actually interact with Superman.
Michael Clarke Duncan would be a good choice for Darkseid. I mean he's a good actor and he's also a big dude that looks like he could take Superman one on one.
Additional cast Kevin J O'Connor as Desaad and Michael Dorn as the voice of Kalibak.
As far as the director goes I would pick Louis Leterrier even though he lied about Captain America being in the Hulk movie he's a good director.