Cry me a river.
That's fine with me. Any writers that would make Lex Luthor's motivation real estate... AGAIN, make Superman an out of the picture father of a bastard child and remove "American Way" from a line that's been connected to Superman for decades are welcome to stay away from the next movie.
As far as is known, Bryan Singer is still associated with the next film but that could change. If the studio isn't happy with the previous film (and although it made some decent money many people were more than slightly annoyed by the items I mentioned above), it's not a stretch to think they may decide to hand the project to someone else.
According to /Film, there's some buzz that they may be looking for a complete reboot of the franchise the same way Universal is with The Incredible Hulk. I find that kind of funny since I thought that was what Superman Returns was originally supposed to do, but instead ended up being more of a new version of Superman III by picking up on the events from the second Chris Reeve movie.
Whether this means Warner Bros. is going to scrap what they have planned so far regarding the plot of the next film or just have new writers come in and build on it or tweak it is still unknown at this point. I'd love to see some supervillain come in and do the old reverse time travel earth spin thing and retcon that kid right out of existence, but that would be too easy.
Hopefully the next villain will actually give Superman a super-villain to fight.
Source: Variety via /Film