So what you're saying is that kids have feet, and those feet come in different shapes and sizes. Fortunately, so do boots.
These endless annual threads only serve to propagate the myth that one boot is the key to successful ruck marching and one is the sure path to failure. Neither could be farther from the truth.
Only one thing matters: buy a boot that fits. Period. Further discussion only seems to obfuscate the issue. Khybers are not "better" than Bellevilles, nor vice versa.
They're big sneakers. Get ones that fit well. Then forget about it.
As an Infantry Officer with a few thousand miles carrying 80 lbs packs, I disagree. But perhaps you have a different perspective from the air.
I suggest a high quality boot, with excellent soles. Yes, they must fit properly, but quality does matter.