What attribute would this be under str or agi, just curious.
You would begin to see builds built around the attribute it is governed by, if you decided to make a build that didn't use the skill then you would be at large disadvantage as you would be allowed less overall quality of equipment.
It'd be funny if a new attribute called charisma governed it though so that noobs could pour points into a useless attribute for less repair costs only to find they have no combat skills