I suggested pretty much this idea a couple of years ago, but it's suffering from a lack of kudos and discussion. The core of the idea is that the BD is the only required part of a VI, but it's possible to add one or more FP views which could give different views for UI, debugging, etc, but only when required. 99% of my subVIs have no requirement for a FP, and I often don't even worry about arranging things particularly nicely, as once created, I never look at it. For example, every Class Accessor VI - why have a FP at all?
Darin's pic is not a bad addition either, though it probably only makes sense for small subVIs - and most are, at least in my experience.