I am a high level crafter (not maxed yet for 70, but sat at 60s for awhile in heavensward). Overmelding takes patience and luck. Overmelding can make crafted high quality gear almost as good as upgraded raid gear. It is a different option for people. The crafting experience is not necessarily one that many people enjoy and thus choose not to level. If you don't like the concept of overmelding, which is explained really well in game by the goblin in central thanalin, just acquire your raid gear or tome gear and apply materia in the slots provided.