I think you are worrying over nothing. I keep my guys barefoot and they look the same.....probably worse. What happens I think that as their feet grow out they start to flare a touch and then that causes some separation at the white line. If you really want to be particular about it, you can keep the feet constantly trimmed and mustang rolled and that should help or eliminate any separation.
But what I find is that if I keep my horses feet super short they are more sensitive in the rocks so I live with a little bit of excess hoof wall on my horses because that way I can actually ride them successfully barefoot instead of booting every ride.
So I try to walk the line of keeping them short enough not to have flare/separation and actually having them functional. I have a friend who never trims her horses but rides them and lets the feet break off. They look awful but are functional. I am not condoning that and would never do that myself, but it just illustrates that a little excess wall helps protect the sole.
So anyway, her feet look normal to me and she actually has a really healthy looking frog.