[@Genkai] Im glad you like the character, I put him at such a high level of smithing as in my head he started at 18 and has travelled to various smiths to gain extra skills. For some faults how about due to working with his hands and up close he is short sighted and on his left hand he has lost the tips of his index and middle finger due to being absent minded and hammering them instead of the piece being crafted. For fighting I would say he is slow, he aims for huge hits which always leaves him open if he doesnt hit his mark especially with a two handed weapon.
Finally him being finicky for me means that he sometimes loses track of the bigger picture he over complicates things when they should be simple. For example of a piece of armour, the person may just want a quick fix to cover the crack but he wants to make the piece even as if there never was a crack. Maybe taking to much time can lead to frustration on some of his clients parts?