Excellent points David. I too wonder what has remain true to NP pizza versus what has changed with time. No doubt, there has been change over time. I can only speculate that the original NP pizzas were more bread than pizza or more bread like in nature and sold in the market meant for food on the go rather than sitting down with a fork and knife. But I know so very little about this style of pizza.
You also make a very good point about the toughness tied to the oven spring. And I would also include more specifically the condition of the dough at bake time along with a proper bake, within a wide range of temperatures. In my limited experience in making various styles of pizza, using numerous different types and brands of flours, hydration ratios, different yeasts, kneading techniques & methods and extent of fermentation, I have also correlated different textures in the end crust with over spring and degree of fermentation. And I would have to agree, that is for the most part not dependent on temperature. It is to a certain degree, but there are many other factors that can affect the end texture both independently and collectively as a whole.
I have experience very very light and airy textures from a 60sec bake all the way to a 8-10min baked pizza and even a 50m baked loaf of bread, regardless of type of flours and oven temperatures. It's all in the balance of the dough versus the heat of the oven. The specific dough and amount of heat have to be made for another. It is the marriage of the two that brings about optimal texture.
This idea that caputo 00 pizzeria flour makes a tough crust at lower temps is a ridiculous notion to me. It does, if the dough is made to sing at a 60 second bake and you bake it out to 3 mins. However, if you make the dough to sing at 3 or 5 or 10m, and bake it accordingly, it will sing for you. I have seen this in several pizza bakes including making a loaf of bread with 00 flour. If I can cook it 40-50m and it still has a tender crumb, then the notion that 00 flour makes for a tough crust beyond a 90 second bake can not be true I say. In theory, I should be able to take that same 00 bread dough and make pizza with it and have a great crust in the 4-5min realm.
But when correlating oven spring with end textures, we also have to consider how the gluten is develop and to what extent. You can have a very strong gluten matrix from over development of the dough (relative to protein content, water, etc), get great oven spring, and end up with a tough crumb, or shoe leather. When I started, I did this all the time. I abused the dough by slapping it around and all I got was toughness in the end product along with great oven spring.
I found that out here...http://www.pizzamaking.com/forum/index.php/topic,11015.40.html
I was upping my hydrations up to near 80% for AP flour and still getting dry tough crumbs. Why? I was over kneading and not developing the gluten slowly and properly. Great oven spring, strong gluten matrix (too strong), open looking crumb, but dry crumb. So spring can equate to proper texture but not always, only if the gluten is properly developed and then coupled with a proper bake.