Mike To answer your question, from my point of view, it is and always should be "ANZAC". I do understand that to use Anzac in a sentence when referring to the Anzacs is correct.
Yes it is an acronym, which represents a group of our two nations highly regarded representatives.
If I write Australia in a post, I write it with a capital "A' because that is the way that I was taught to write the names of Countries, peoples names, the month etc. I try to do it every time out of respect.
It seems to me that Australia is somewhat guilty of claiming ANZAC day as it's own. (google "Anzac day" for evidence)( Mike, I know your views on wiki
) I think that calling it "Anzac" day helps to to further diminish New Zealand's part in this.
I believe the acronym should be all in capitals because "New Zealand" also deserves the same respect as "Australia".
BTW for WWI, As a percentage of the population, New Zealand's commitment in the way of lives lost, and injuries, was higher than any other country. If I remember correctly,something like 40% of all males between 18 and 40 wore a military uniform, had served over seas, or were in training.
There is a strong brotherhood between our two countries. The commemoration of the price paid, in a similar way, by both countries, strengthens that bond.
Just my view.
Cheers Mike
