If you choose to pursue this avenue of planning software development, make sure you do it on a huge project. I've just given up trying it on a small one -- it feels like it's turning the small project into a huge project. I could have coded and released the darn thing in the time it's taken me to specify half of it accurately.
That being said, I will be going back to my old ways with the Inukshuk CLI Utilities -- and those who are interested will see results much more quickly.