I love the idea and it is actually such a nostalgia element from classics like Neverwinter Nights, where we had a smith that could upgrade some equipment in each town. By the way there was another restriction for enchantments in the main campain. You needed to bring +1/+2/+3... weapon to the smith. You would lose that bonus, but would get some fancy magical property in return. And in Hordes of the Underdark there was a famous master smith that would add enchantments to your weapon again and again for a good price. I loved how I could bring him some weapon I just liked from aesthetic point of view and turn it into an Ultra-Mega God-killing weapon.
