That is a great question! I think our requirements for greenfield should be more relaxed since we'll be iterating faster (and there's a significant risk that the greenfield project won't succeed). My concern is that time and time I've seen somebody write code for greenfield, and the thing really takes off and that proof-of-concept code becomes production code, while it was never intended to be production code. I've been guilty of that myself. There's code in production today that I never intended to be production code!