A lot of us agree that how Apple did this is stupid. Resurrecting a thread that is a year and a half old is probably not the best way to express it.This would seem to be a problem with the logic of calling it a Camera Roll. It all started in the real word. You shot a roll of film, it had only the pics you shot, you took it in and developed it and got the prints you wanted. When you put in a new roll you DID NOT have all the previous pictures. It would have made sense (from a machine sense) that there is a pile of all pictures somewhere and then just use pointers for organizing. But something called Camera Roll should only be the pointers to what you recently shot. Then you would move the pointers around to organised folders. You should then have the option to set the camera roll as groups with the same date, or a set quantity, or whatever.
It would just be nice when you opened the Camera Roll to only see what you took in your last session, and not the whole pile you have taken since time began. It would make selecting and moving them to albums a little easier. IMHO
That said…
Jailbreak. Download from Cydia one of the two or three tweaks that fix this and allow you to make it the way it should be. Done.