I don't see how crafting and repairing enhance the non-combat experience of the game. Both crafting and repairing are pretty much only useful for combat.
It encourages actually reading the craft books, exploring the item creation for things like sneaking and pick pocketing and luck. Maybe even the dialogue stuff with +Persuasion gear.
It would give player options outside of just leveling and RNG loot. Heck, through in a quest or two that requires it to solve.
While the skills are mainly combat oriented, it helps with pretty much everything. Also, I think it's rewarding to have a different methodology for how a player approaches getting his character ready for combat: one guy might prefer making powerful gear and buying and selling stuff to outfit his group....another might prefer strong abilities. Late game would let you do both or specialize in one while letting you make good headway on the other.
It can only add to the game *shrug* in my opinion, at least
EDIT: Let me just throw this out there, I'm a strong RPG fan...have been for a while. I'm also a fan of Oblivion and Skyrim and doing all the little side quests (ie mining in Mass Effect). Grinding, repition of small tasks, ect doesn't bother me in the least as long as I feel like progress is being made somewhere. At the moment, repair feels like it does nothing but wast time...I'd just like for that time wasted to feel like it was important in some way and exanding on that I can see how it could add complexity. Heck , I can spend 30 min to an hour just buying and selling and crafting in D:OS on every level up without even noticing; it gives me more items I might need or can sell, which means more money, which means I can buy other things I want, and crafting also allows for min-maxing powerful gear
