I deeply, truly, desperately want Apple to add a Files app and DocumentPicker controller to the iPhone and iPad in iOS 8. I've wanted it going on 4 years, and every year more than the last. It is, in my very humble opinion, one of the biggest, most frustrating holes remaining on Apple's mobile operating system, and all the more so because it seems like a model for fixing it has been in successful use for years already. Right now we're saddled with the complexity and frustration of iOS documents locked in app and iCloud jails. We're driven to outdated filesystems like Dropbox because Apple hasn't yet provided a next generation alternative. It needs to happen and so I'm once again asking for it this year and for iOS 8.
iOS has many complexity-inducing frustrations born out of "keep it simple", but none as big as this one. File handling on iOS is so incredibly frustrating and needlessly complex that I have a hard time considering it a mature operating system at all. My line of work requires constant opening and closing of a quarter metric frickton of files, and that kind of stuff is simply impossible on iOS.