Maybe a bit of the topic, but why not have merchants (both players and NPC) that actually sell ignots and bars of metal, can be same with leather worker merchants that actually sell finished patches.
Crafting now, at least some crafts is really time consuming... and as i see it, far from every smith and leather worker mine or hunt for hide them self's.
Also another way mentioned here is to hire people to mine for you, or hunt for skins or what ever you need for your craft.
But i am not one that would complain if the dwarfs or some other NPC merchant actually started to sell allready mined ignots, then you have an option... mine it your self and save you gold, hire someone to mine for you, or spend your hard earned gold and just buy it ( if you can afford that ).
To say certain classes may have it more easy, well..maybe... that would depend on the build more then the actually class..but to assume all rogues is DEX based is way wrong, same as to assume all fighters have great strength.