This will give you the quest Boon of the Nether Disruptor. 'Artisans of the highest level will receive commendations for their efforts, allowing them to craft the most Legendary items of items.'

Have the building Nether Disruptor up for the trait: Armorcrafter Commendations.

Completing the Broken Shore scenario that you can do directly when you log on when 7.2 is live.

In PTR it, is not clear when you can actually start this quest line but you will most likely be able to take the quest after Patterns are available in Dalaran in Broken Shore. Go to the tailor in Stormmwind (alliance) or Orgrimmar (horde) to learn the pattern (Dalaran in Broken Shore doesnt give the pattern. It costs 8000 Nethershards which is a currency in Broken Shore. This item is bought from Warmage Kath´leen in Deliverance Point. You can craft one legendary only, every time Nether Disruptor becomes active. More specifically, Leatherworker can craft 2 (1 leather and 1 mail), Blacksmith can craft 1 and Tailors can craft 1. If you need help on running SimulationCraft, developing custom actions lists, or have other questions, please see our extensive documentation or check out our Github project page.In patch 7.2 you can craft Legendaries. We are continuously looking for new profiles, both at the normal and heroic levels. In addition, inefficiencies (talents, gear, gems, enchants) may be found in the supplied profiles. After examining the reports, players may detect inconsistencies with their experiences in-game. It is important that information flow in both directions. This provides players with easy access to simulation results at various gear points and patch levels. The primary purpose of this site is to host sample analysis generated by SimulationCraft. The goal of this simulator is to close the accuracy gap while maintaining a performance level high enough to calculate relative stat weights to aid gear selection. Increasing class synergy and the prevalence of proc-based combat modifiers have eroded the accuracy of traditional calculators that rely upon closed-form approximations to model very complex mechanics.

Wow legion ptr 7.2 legendary