Well, I have many ideas for crafting, but they're all still in the notebook stage, so at this point, really hard to tell.
However, I think it's safe to sell the most common stuff, like ruined skins and small gems. I will not make an extremely "grindy" crafting, that forces you to make the same piece of armor 200 times.
Crafting will come (in part) in 0.8, I expect 0.7 to be finished this month, and then I'll open a thread with some information so you all can provide feedback.