in Next weeks patch

Changes to Legendary Drops:

Legendary Drop Rates, across the board, will be increased by 100%

Legendary Level Brackets will be removed, so that all Legendary items can drop at any level.
Previously, some items could only drop from enemies of certain levels or above. For example, the Ugake Cowl could only drop from enemies of level 48 or higher.

Legendary Anti-Duplication System will be implemented

This system will mean that if a character has an item in their inventory or stash and a duplicate item is rolled, the dropped item will be re-rolled once.
Note that this system does not guarantee that every drop will be unique. Rather, it is designed to provide a second roll at avoiding a duplicate.

Scripted Boss Loot (Chrysaloid, Yagak) will be able to drop all non-class specific Legendary Helmets

This change will improve the variety of items in the Campaign.
Previously, these bosses would only drop a selection of Legendaries (the same pool that was available in the Demo as well as the Cannonball Helmet).

The Luck system will be improved and players should no longer experience very long droughts without a Legendary item dropped during endgame.

The base scaling of Legendaries dropping through higher difficulty levels still applies, so you may will still want to farm as high as possible.