Yes. I think we're saying the same thing.

By "link" I specifically meant data, not functions. Because everything is potentially visible, FP requires you to keep track of data structures in your head -- sometimes complex data structures with non-trivial relationships to other data structures.

Of course, there are methods to keep it simple -- starting small and growing as needed comes to mind first -- but if you're writing FP in a legacy environment with lots of nasty complex data structures you have a big headache. This would not be true in the same data environment with a well-constructed OO tier. [insert discussion here about what makes a well-constructed OO tier]

Or maybe I missed it. If I did, please straighten me out.