First off, if you're interested in such, Love and Pop has my review of HP Lovecraft's The Thing On The Doorstep. It's mostly good but an unfortunate shade of murky green.
However, there's one particular argument I hear from people in favour of keeping the current flag, which I think needs to be disposed of - the idea that you can't change the flag, because New Zealand soldiers died under it*.
I'm loath to Godwin myself so easily, but here's a flag people died under:
and here's another:
here's one people are dying under right now:
It is entirely possible for people to commit themselves sincerely to a cause, and its symbols, and be wrong. It is equally possible for people to be misled as to the actual purpose of their actions - this is my view of soldiers who died in WWI in particular. Enshrining symbols and the causes they represent, just because people were willing to die for them is a terrible idea.
*Lest you think I'm overstating this, the NZ RSA wants people to spoil their flag ballots for this specific reason.