A quick glance at some of the other responses finds me agreeing and disagreeing. A certified Natural trimmer can help (Is your farrier taking off sole?).
What got my QH gelding over the hump was hoof boots. I tried several different brands and found that for him SYMPLE boots worked the best. There are now many brands. Hand walking him on pavement for 20 minutes a day for several weeks also really helped to change things.
Not all horses can go barefoot but the right trim with the aid of boots for riding can help. It requires a commitment on the owners part and some people are just not willing (sometimes not able) to make that commitment.