:P
It's important to note that we abandoned (or "put on hold") Lunascript, but not Luna. The vision for Luna always revolved around making it easy to write bug-free, real-time, responsive, collaborative, interactive webapps. The syntax of Lunascript over directly using the framework in Javascript was always a nice-to-have.
I'm not denying your lesson, of course. To this day we still have some Lunascript in the codebase, and it does create some developer friction that costs real time. In retrospect, I'm sure it seems obvious that we should skipped the language and just built the framework.
However, it's important to understand that the language itself was built mostly by Justin very early in the company's history, and basically no work was poured into it after we hired employees and built out the product. One framing of Lunascript is two guys taking a few months to try a few big ideas out before building a company they want to do the right way. We always knew we would have to compromise on ideals once we moved forward, but we wanted to see what stuck. I think a lot of the reason we're under scrutiny here is because people look at the time since D+J left Facebook and are like "what did you guys do with all that time?" The answer is the company didn't get started in earnest until almost a year later when we hired Greg and Malcolm.
This is a totally legitimate point. But it's not that we're not fans of MVP, we're just also fans of vision-directed products like Facebook and Apple.
We have some people who are more MVP-leaning, and others who are "let's build the vision"-leaning. For example, Eric Reis is one of our board observers. But we all believe we should't fall back on dogma rather than using judgment and balance, and we think having a symphony of perspectives on the issue is valuable to deriving that balance.
We're committed to validating our hypotheses via customer adoption and metrics, but we're also committed to investing sufficiently in our framework, platform, and product that we can realize the whole of our ambition. Practically speaking, the user feedback right now is very consistent, and we know where we need to go. We absolutely need search, for example. Adding tons more users or doing more rigorous validation would slow us down from getting there. As the path ahead of us gets less clear, we will scale up our userbase and invest more in metrics and validation.