This is a great question, so long as people really, truly, deeply, understand the part about "the most important thing" and not just the "smallest step". Maybe it is better phrased as "What is the next most important thing we can do and what is the next smallest step we can take to validate and bring it into motion?". This is, of course, the basis for Gilb's EVO approach, which predates agile in its origins by at least a decade.