I would vote against any crafting class being able to repair any gear - I know it's a video game, but I liked that there was a correlation between crafter class and the goods they make & repair and the mats they use. I do not like the idea of whipping out my saw to repair your plate armor (although I guess I have an off hand hammer I could bang on dents with).

I think Plan B is sufficient. If NPCs can repair jewelry, and they are at all the camps and cities that is leaps and bounds beyond what we have now for repairing jewelry. But moving all the way to Plan A would essentially eliminate the need for GSM repairs which would make GSMs sad. I don't understand why accessories should be treated differently from other armor types. However, I think it would be nice to have more accessories that can be made by other classes and balance out the single repair class reliance on all those slots.

EDIT: I also like the idea of repair kits that adventurer's could buy to use in the field (ie...standing around outside Darkhold trying to get gear fixed, or for when doing extended exploring away from camps.)