I also hate that, but there's is a tweak which helps me.
I use "PhotoAlbums+ for iOS 7 and iPhone/iPod" for my iPhone
You can actually "move" instead of just "copy"/"link" pictures from the camera roll to other folders.
Another walk around are apps which organize your camera roll. The create folder and link all pictures respective to their format, e.g. Folders for panoramas, taken photos, videos, screenshots, downloaded pictures etc.
I tested some and they work very good and are incredibly fast.
One good example is "Smart photo organizer":
https://itunes.apple.com/de/app/smart-photo-organizer/id580797271?mt=8&at=10l3Vy