Co-screenwriter, Marc Guggenheim talked to MTV about how the writing is coming along. He mentioned that Oa will look amazing:
[T]he shots on Oa are spectacular. What Oa looks like has never been seen on film.
What got my attention is the mention of cameos in the movie. He brings up some good points. He is for the "easter eggs" but you do have to be careful about them. Too many could be distracting. Then there's the casting. Would casting an average actor harm any chances of that character appearing in their own movie later? If Tom Welling was used as Superman, would that limit the movie to Smallville's (television) universe? Should Brandon Routh be used when it's possible yet another actor could be wearing the red and blue tights whenever the next Superman movie flies into theatres?
Some easter egg cameos would be nice but should be handled carefully.