Imagine that you're creating a presentation on an iPad. You want to create a presentation, add content to it, and rearrange it as needed. You have a catalog of content to choose from, sorted by category, accessible by left side slide out navigation. Aside from some of the obvious constraints, an important constraint to consider is that your users primarily navigate to content based on its location in the catalog, not by name.
Now, is better to:
A) Have the presentation you're currently working on open as a small column on the right side of your screen that you're able to drag and drop content onto? This column would persist through navigation until dismissed.
b) Navigate to content, and add it to your presentation (not visible) file picker style action? This action would be most similar to an "export" or "save as" type feature, where the location you're exporting the single presentation to is the presentation you're working on.
c) Open your presentation, and add content to it via a file picker side pane. Essentially the reverse of option A. You'd navigate to your content in the same way that you would for option A, but in a smaller, minimized view.
Any thoughts or ideas appreciated :)