I wore hiking sandals the whole CP way. After experimenting, I found that socks and sandals were the most comfortable--people along the route did ask one or another of us (there were three of us walking) if we (or at least I) were German. Must be a stereotypical trait, wha?!
(Since Sebastian, one of my Camingos, IS German, he got a great kick out of people asking him if I was!)
I found the sandals worked for me, though I don't think anything much less floating above the ground, would take the stress off of anyone's feet after walking on cobblestone roads day after day after day.
Enjoy your CP walk! It's a fantastic Camino!