Here's something that just occurred to me; The Byzantium still crashed. Angel Bob never existed, but the Byzantium was still sabotaged, and River Song was still sent out by the Church to infiltrate it and secure the crash site. Given that the soldiers in the ship had their memories lost to the crack, we can't just assume everyone in the 51st century has travelled in time and is insulated from the crack's effects. And River isn't a Time Lord, so she can't remember both versions of events the way the Doctor can. So when she got back to prison, what the hell did they think they sent her out for?
I'm thinking there may be quite the little subgenre of fanfic opening up, with rewriting the "Time of Angels" episodes as River's benefactors remembered them, without any actual angels, and, well, hell, pretty much the entire season to this point with how Amy now remembers it.
Maybe she's getting married to Jeff, instead. That'd clean up a lot of loose ends.