I've fixed this sort of damage. The one on the left there, where there's a little flap of leather lifted up, glue back down with Titebond 3. It's water soluble until it dries, so you can make sure with a slightly damp rag that there's no glue left on the surface. Then, as the above savants have opined, fill the scuffs with wax polish, using fairly heavy applications and buffing off, repeat repeat. The trick is in how you buff. After three or four tries (by the time you have the scuffs filled) you'll have the lick right; how to buff off the surface without pulling the wax out of the scuffs. Lightly and quickly, after letting the polish dry quite a while.
I've taken a fairly cut up pair of shoes and disappeared the scuffs so that you have to hold the shoe right up to yer schnozz to see the thing. Down at foot level, it's good.