Don't know whether this is still an issue for you, but just to let you know that rearranging photos and videos in the Camera Roll is meanwhile possible. There is a way to reorder the iOS Camera Roll on iPhone and iPad, be it to sort it by date taken or order the items manually as you wish. To this purpose you need a complementary photo library like the Utiful app. Once you have such complementary photo library, you can move the photos you want to reorder to it, reorder them there, and then move them back to the Camera Roll. Done, the photos are now back in your Camera Roll in the order that you wish..