Like many, I format my writing structure in a tree. Within each branch of that tree are multiple documents. These documents make up the sections of the overall publication that we are writing. In the iOS version, it’s not possible to rearrange the sub-documents that are part of the branch. That functionality really needs to be there. I’m sure that I’m not the only one that doesn’t want to have to login to the OS X version just to rearrange sections of the writing.
I’m not quite sure which functionality you mean isn’t there. You can move items as freely in iOS as you can in the desktop versions. You can drag and drop in the corkboard by holding down a card, and you can drag and drop items in the binder in “Edit” mode to arrange them in any order you want.
There’s even a movement mode in the binder that allows you to move items up, down, left and right.