Brace yourselves...
I agree with you, Bill.
I gave the what on interchange, and you gave the wherefore.
My comment in this thread was meant to be pretty limited in scope: we were talking about FCPX as an editing assistant, rough cut, or offline editorial application, so naturally interchange would have been an important part of that. If you can run your edit from start to finish in FCPX, you don't need interchange. If you need more capability than FCPX currently allows, though, interchange to another app that offers that capability will be a challenge.
Walter Soyka
Principal & Designer at
Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events