Personally I think we should just be able to meld to basic slots without a crafter or an NPC, the slot is there, you're literally just sticking a ball in a hole. But with advanced melding it makes sense to need a crafter, you're basically shoving the materia into the gear and I can see how a crafter might be needed for that. We don't need an NPC, just let us meld basic slots without a craft and leave advanced melding as is.