Lads, it's not like they're talking about rolling them into one OS by next Tuesday,
This is coming a long way down the line.
By the time OSX and iOS are fully merged, "computers" will be practically unrecognisable from what they are today,
And will call for a whole other kind of OS than what we're accustomed to.
The one thing you can bet on is the whole 'desktop' metaphor being ditched in favour of something much more intuitive.
As for the file system, the overwhelming majority of computer users either:
-don't understand the file/folder system
Or
-they don't really use it in any significant way.
As such, the whole 'office' based UI of a desktop and filing cabinet is on it's way out, as it is demonstrably a failure of human-computer interaction.
In short, I wouldn't worry about this having any real impact on what we do today, ad the people who eventually use iOS-X will consider our current operating systems as archaic as a PDP-10 timesharing mainframe seems to us today.