Goldman's quote (I think it's Goldman) refers to the protagonist too, so it's not necessarily true that the end of a war be the most important story to tell. Different people are going to remember different events in their lives as being the most important. Your WW2 example is a good one for this, given its immense scope. A little girl growing up in occupied France might have the defining moment of her experience be tasting chocolate for the first time after being liberated. The most important event a 19-year-old soldier from Brooklyn might have would be storming the Normandy beach and having his best friend killed. Someone in Bulgaria is going to have a completely different life-defining moment during the war as someone in Egypt. And as the war effectively ended at different times for different people, the end of the war becomes an elusive issue.
Also, in the specific case of WW2, it wasn't one climax that ended the war but an inevitable conclusion that was dragged out over many years. It wasn't an attack on the death star or beheading of a snake. Instead, you have lots of key turning points, which I would argue are much more dramatic than the final surrenders. I wonder whether Montgomery looked back on accepting the German surrender or defeating Rommel at El Alamein as the most important thing he had ever done? We have two films about Pearl Harbour, the start of the war, but I don't think we have any that show the Japanese surrender on the Missouri. Looking back on Band of Brothers, the last episode is probably a bit anti-climatic even. One of my favourite WW2 films is The Heroes of Telemark, which is about Norwegians delaying German development of the atomic bomb by destroying their heavy water stockpile. Did it kill thousands of young men or involve capturing a strategic bridge? No, it's one of many key moments contributing towards the allies' ultimate victory.
I'd argue that a good test is to ask what if it didn't happen? What would the character have become? What would the universe be like without that event?
There was a recent story in the papers over here about how at the start of the first world war, Britain sent over untrained volunteers at the very start to help shore up the defences in Belgium to give time for the main force to arrive. They were all killed or captured but ultimately stalled the German advance enough to create, in essence, the stalemate that would later claim so many lives. They arguably changed the course of the war and history, but remain unknown and unrecognised. History is full of such stories.
You also have to factor in proximity to the event. Take 9/11, that has to be the most important event in a lot of people's lives - yet the subsequent invasion of Afghanistan could be a mere footnote to those same people. Conversely, you have people there at the start of a conflict like Iraq who couldn't care less about the end of that conflict.
Interesting that you bring up Pacific Rim, as I feel the story we got was the least interesting 'expression' of that universe. The wider world in general excites me, from a conceptual point of view, but the movie is a poor execution of world-building (lots of things don't really make sense, and it contradicts itself). The prologue scene is the best part of the movie, and I want to see that movie. Here I think it's a case between important vs interesting. For the main character, the most important moment in his life was probably in the first act. I do think that the first Jaeger is a far more interesting story to tell than the last Jaeger, though that could just be a case of not liking the story they told about the last Jaeger.
