Allen's context is defense procurement, however his formula will resonate with solution vendors and IT architects across the board. The next step is to get people to see that “flexibility” isn't the same as “peculiarity”. The aim is to do processes well, not weirdly. In achieving excellence in process delivery, systems designers will inevitably find themselves coming up with similar solutions to common problems. That's what the software design patterns movement is all about.
Designers need to concentrate on the real differences in their approaches to a business problem or challenge, and not be afraid to reuse answers that others have proven. This is the sense of “flexibility” we should have in mind when we cheer Allen's slogan.