According to this video http://www.youtube.com/watch?v=10YwzynVwgY you will have to do every aspect of the game to get the best gear. So crafting will propably only get you BiS gear for certain slots.
but from this info, wouldnt you still need crafting in order to make your item the best you'd want it to be, more than just a simple enchant, but you'd enchants AND upgrades!
so certainly in a way, in order to get the best gear, you'd need the help of crafters.