Most people who want better photo organizing options go with third party apps like; Photo Manager Pro, Photo-Sort, or Photo Shack Pro. Do a search in the App Store and read the descriptions. A search in the forum should net you plenty of member opinions on each, and a rough idea of what each can do.
With he exception of Photo Shack Pro, most of the apps keep a separate database of photos. Sometimes that's a good thing, and sometimes it's not; all depends on what you need to do with the photos.