Crafting is a double-edged sword; The problem with crafting in RPGs is that it devalues adventuring. My personal view on the matter is that loot should come from killing things, finding hidden treasure and completion of quests. Not combining cowskin with needle and thread to make [Best Boots in the Game] without ever having to leave town.
This is not an issue if some rare materials come exclusively from powerful bosses.
I prefer crafting the most powerful item since it makes the process of obtaining gears more memorable. RNG may also be controlled if players are able to craft gears for different builds with the material