The game already has a mechanism in place for crafters to self-adjust the HQ/NQ rate: Bold vs Standard. This system could be elaborated, but tweaking HQ rates doesn't address underlying issues. If the HQ rate is too high, you flood the market. If too low, you spend your time repetitively crafting and hoping. Neither is a good situation.
Making HQ items require rare ingredients is one solution. If the rare item is an NM drop, then the crafter is left on the sidelines, only called into action if a drop is obtained. If the rare ingredient is a rare crafting result, then you're back to repetitive crafting.
It would be nice if there was an NM equivalent for crafters. HQ results for extraordinary effort. As it is, once you have your materials, crafting mundane item-X is just like crafting exceptional item-Y. The process is the same. The challenge is in obtaining the proper materials or else in spamming long enough to get lucky.
Imagine if instead of fighting a challenging NM the DoW/DoM only fought normal dodos and got the valuable drops only if they popped the dodo with a rare pop item or else slaughtered enough common dodos to get a rare drop. Wouldn't be very satisfying.