They should at least softlock it so you have to spend dockets/materials. Probably would make Melk redundant 
Even though at this point you don’t need ideal weapon to finish T5 missions. It is now matter how effective/fast you can do it with better weapons. To feel and be more powerful.
Part of me just wants conclusion. If they just say they won’t unlock, just say it and then conversation ends there, so we won’t be holding out further hope of crafting freedom.