I always tell him he is not giving our ancestors enough credit.
That sir, is the truth!
So after a full weekend of wearing my turnshoes all day, they gave me no problems. The only issue I had was one of my shoes coming untied once, but that happens on any shoe, modern or medieval.
I wore them on pavement for a time, and of course they're not that comfortable on pavement since there's no padding, but what I did notice is the wear on the sole was minimal which was a pleasant surprise. It rained on Sunday afternoon while we broke down, and I literally ran in them on wet grass and no slippage!
Came home and oiled the leather with neatsfoot oil and they look no worse for the wear. Overall, I declare them a success. I will make a second pair when I get the chance so one can serve as arming shoes, and the other will not have pointing holes in the toes.