Experience... absolutely. And when someone posts their wood usage and pre-heat times with a lower door FGM, I will defer to that experience completely. Until then, though, this is largely theory.
Theory and history. I'm well aware that some of Marco's beliefs are not universally accepted and I also believe that Neapolitan oven builders can be wrong. At the same time, though, I strongly believe that we can learn from the Neapolitans and that, without evidence to the contrary, when it comes to oven design, the Neapolitans get the benefit of the doubt. Just because we don't have any Italian oven builders on this forum doesn't mean that their opinions don't carry weight. If their oven has a particular specification, and we can find a relatively easy way to match it, then we definitely should, until it is proven as being inferior.
Between French (or any other nationality) oven builders baking pizza at 600 degrees and Neapolitan oven builders with more than a century of making the exact pizza that we're all striving for, I will ALWAYS defer to the Italians until I see hard evidence to the contrary.
The low doors on all Neapolitan ovens are not there by chance. They're not an aesthetic decision. They are their for a reason. Until they are completely proven as unnecessary, I will continue to fight tooth and nail for them.
The Italians aren't always right, but until proven otherwise, I defer to their experience.