Wait, how can you get stuck when describing the product ‘because it’s just assumptions?’ In my experience, all the assumptions are typically about the problem and the customer. The solution is rarely bottlenecked by assumptions, because you can make tradeoffs as you’re writing the PRFAQ and making up the solution (constrained by the fact that it must make sense and be compelling to a potential customer).
If you can’t make the solution sound compelling in a PRFAQ, you shouldn’t continue.
Hmm — no, the clarity came from understanding the customer and how they saw Commoncog and what they wanted out of Commoncog.