I think with (b) the poster is talking about the totally idiotic way you move files between applications on iOS.
Say I have a text file created in one Application and I want to open it with another to do some formatting then open in again in the original application. On a sane system I'd have some sort of file browser I can use to locate the file. On iOS you have to send a copy to the other application, modify it, hope it knows about the original application so it can send it back, send back another copy of the file. It's a huge mess. It means you only ever bother to get documents onto iOS devices to view them and never bother trying to edit them there for fear you'll never be able to keep the dozens of eventual copies in order.
Even iOS applications that have native support for WebDAV manage to screw up and make duplicates of things all the time. The iWork apps on iPad are great examples of this. You wan't to work on something on a WebDAV share? Sure, here's a copy. You want to save those changes back to the WebDAV share? Ok, I'll just make another copy....
I hope that at some point Apple figures out that everybody hates their iOS file swapping system and at least gives us a walled of file area that we can access via WebDAV or over USB. Applications should then just pick files from that common area rather than maintaining their own duplicates of everything.
Access to the root filesystem of the device would be even better but I know that's unlikely to happen.