My shoes, both pairs have 4 large holes in them. My feet are as tuff as nails where these 4 holes are. This has made it easy to get use to the rocks/cold, etc. I find myself running on the gravel and ALWAYS on the tip toes, because the soft arch does not like sharp rocks..........................
More and more, I see the shoe as a bad thing. So far the only trouble I have ran into is glass. Other wise my feet have adapted well and when I do slip a pair of shoes on, my feet sweat and feel suffocated very quickly.
To place a pair of shoes on a runner, could only hold their feet back.