I still think that we're missing a trick in terms of the starting point for a discussion.
It's impossible to talk about the role and design of the national league without considering the wider strategic context of elite football in NZ - specifically professionalism. There's clearly a view amongst some that the national league should be the vehicle to deliver elite, professional football in NZ. I personally doubt that's actually possible but it's still a valid point of view. On the other hand you could argue that's what the A-League gives us and we should focus on developing additional A-League franchises as the way to expand professionalism in NZ. If that's the case then the national league probably starts to look more like a development/feeder type of league that supports that.
Either way, it seems to me that it's impossible not to discuss the role of the A-League in NZ first because that then fundamentally affects what the national league is about.
EDIT: btw, I think the creation of the A-League, and the success of the Phoenix as a viable entity within the A-League, is probably the major environmental change we've seen since the NZFC/ASBP was launched. It really can't be ignored.