Honestly, I like the way Apple is moving with Mountain Lion. Only app or OS X feature I'd like to see on my iOS devices is something like Little Snitch where I can see who/what is accessing the internet and possibly what information are they trying to gather.
File System, meh. I wanted a true iOS file system when I got my first iPhone in 07. Since the 3GS in 09, I haven't cared about it. I have apps that can access parts of the phone in case I need to upload an picture, video or whatever.