they turned unique mats into irrelevance. so more stash space hurray

what do you mean ?

no the blacksmith plans remain the same.
All that changes is you don't need unique mats from unique monsters e.g. cain set use to be had to farm maghda. Or reaper wraps had to farm malthael. Now no longer have to 

You just need the plan to craft. After playing for a month or slightly more, your bound to have collected all the plans, because it doesn't drop dupes, and only the ones you are missing.

u can sell the required legendary item such as adventurer journal, reaper's fears, twin seas and etc